This work was carried out in the framework of the project &#8220;MIRAGE,&#8221; funded by the European Commission within the FP7 program.

1. 리프트를 이용한 플립 칩 본딩 NOTE : 거기, LIFT 이용한 플립 칩 어셈블리 LIFT 기술을 사용하여 기판 즉 마이크로 범핑 실현 열 압착 플립 칩 접합 방법을 사용하여 범프 기판에 광전자 칩 부착에 관여하는 세 단계가 있으며, 결합 어셈블리의 마지막 캡슐화. 각 단계는 다음 섹션에 설명되어 있습니다 : <ol><li> 리프트를 사용하여 마이크로 범핑 : <ol><li> 도너 준비 기간은 레이저 투과성 캐리어 기판 상에 도너 재료의 박막을 증착. 이 실험을 위해, 치수 유리 캐리어 기판 위에 인듐 금속의 200 nm 두께의 필름을 증발 : 직경 2 인치 X 0.05 cm 두께. 주 : 기부자 제조 방법은 예를 들어, 증발을 사용하여 고상 도너 재료 스퍼터링 스핀 코팅 및 닥터 블레이 딩을-액상 공여체, 도너 물질의 위상에 의존의. </li><li> 수신기 준비를 들어, 수신기 등 5 × 5 × 0.07 cm 3 차원 유리 기판을 사용합니다. 패턴을 포토 리소그래피를 이용한 구조 프로빙 OE 칩과 팬 아웃을 접합 금속 접촉 패드와 이들 기판. 이 실험을 위해, 패턴 4 μm의 두께 니켈 - 금 본드 패드 및 팬 아웃 유리 수신기 기판 상에 트랙을 프로빙. </li><li> 다음으로, 수신기와 접촉하는 기증자를 배치하고 컴퓨터 제어 XY 번역 무대에 기증자 수신기 어셈블리를 탑재합니다. 참고 : 도너 재료 (예를 들면, 고체 (인듐) 또는 액체 (잉크 / 페이스트)) 그 두께, 도너와 수신기의 기판 상에 따라 쉽게 예 그래피 (제어 될 수 최적의 분리에 배치되고 ) 금속 스페이서를 사용. </li><li> 도너 substrat 통하여 상기 빔 (20 μm의 스폿 크기)를 초점 거리 160mm의 대물 렌즈를 채용 캐리어 도너 계면에 입사 레이저 빔을 초점 스캔수신기 본드 패드 상에 도너 마이크로 범프를 전송하기위한 E. 270 엠제이 / cm 2의 플루 언스에서 수신기 본드 패드 위에 인듐 범프를 들어 올립니다 355 nm 파장과 12 PSEC 펄스 지속 시간의 피코 초 레이저 소스를 사용합니다. 참고 : 에너지와 같은 레이저 특성을, 아니. 펄스, 대물 렌즈의 높이, 인쇄 공여체 마이크로 범프 수신기 기판 정확하게 컴퓨터 프로그램에 의해 제어되는 전송 될 원하는 패턴에 정밀한 위치 조정한다. 중요한 실험 파라미터 (예, 전사 플루 언스)는 다른 레이저 광원을 사용하는 경우에 최적화 될 필요가있다. </li><li> 두꺼운 범프는 새로운 영역으로 기증자를 이동하고 단계를 1.1.4 여러 번 반복하십시오. 예를 들어,이 실험에서 서로의 상단에 인쇄 6 인듐 범프 스택을 얻는 단계 1.1.4에게 여섯 번 반복. 최종 범프 ~ 1.5 ㎛의 평균 높이의 20 μm의 (도 2)의 직경이 해제. 참고 : 이러한 experim 들어엔트 범프의 표면 프로파일 및 두께는 광학 프로파일로 미터를 사용하여 측정 하였다. (그림 3 노란색 표시로) 그것은 범프 1.5 μm의 평균 두께의 볼록 / 돔 형태를 가지고 있음을 확인 하였다, 범프의 직경에 대해 평균. 그 이유는 도너 레이저 조사 영역에서 용융 전사 후 펠릿 (인듐 저 융점) 수신기 표면에 도달하면 다시 고화 것에 기인한다고 생각된다. 이것의 장점은 VCSEL 접촉 패드에 프린트 범프의 양호한 접착 성을 초래한다는 것이다. </li></ol></li><li> 이 칩 열 압착하는 기판 (도 4-6) : <ol><li> 범프 기판에 광전자 칩을 접합하기위한 반자동 플립 칩 본더를 사용합니다. </li><li> 범프 형 수신기와 칩 본더의 각 진공 플레이트에 결합 될로드. 활성 영역 FAC으로, 즉, 대칭 위치에 칩을 놓습니다늦추십시오. </li><li> 적절한 픽업 도구를 사용하여 칩의 중심에 맞 춥니 다. 도 5에 도시 된 바와 같이 바늘 형상의 툴을 사용한다. 다음에,이 픽업 도구를 이용하여 칩을 선택한다. </li><li> 카메라 정렬 시스템을 이용하여 수신기 기판상의 대응 접촉 패드와 칩의 본드 패드를 정렬. </li><li> 일단 장소를 기판에 칩을 정렬. </li><li> 전기 및 기계 상호를 기판에 칩을 실현하는 동시에 열 (~ 200 ° C의)와 압력 (12.5 GF / 범프)를 적용합니다. </li></ol></li><li> 결합 어셈블리 (4-6도)의 캡슐화 : <ol><li> 주사기 바늘을 이용하여 접합 조립체의 가장자리 주위에 광학적으로 투명한 접착제를 디스펜스. 캡슐화는 결합 어셈블리의 기계적 신뢰성을 증가시킨다. 결합 칩을 캡슐화 NOA (86)과 같은 단일 성분 UV 경화형 접착제를 사용합니다. </li><li> ~ 30 초 동안 UV 램프를 이용하여 접착제를 경화. </li></ol></li></ol> 보세 수직 공동 표면 방출 레이저 2. 특성 (표면 광 레이저) 주 : 제작 한 후, 다음 단계는 접합 조립체의 전기 광학 성능을 평가하는 것이다. 소자의 광 전류 - 전압 (LIV) 곡선은 프로브 스테이션을 이용한 포스트 - 본딩 기록된다. 다음 단계는 테스트에 참여하고 있습니다 : <ol><li> 주문 제작 투명 무대에 장치를 결합 플립 칩을 놓습니다. 스테이지의 VCSEL에 의해 방사 된 광에 쉽게 액세스 할 수 있도록 중앙에 뚫린 구멍을 갖는다. </li><li> 투명 단계 아래의 광 검출기 (PD)를 놓고 현미경을 사용하여 결합 된 칩의 활성 영역을 맞 춥니 다. </li><li> 정확히 현미경을 사용하여 패드를 프로빙 니켈 - 금에 프로브 바늘을 놓습니다. </li><li> 전류 10mA까지 주입 한 VCSEL 양단의 전압 강하 및 전류 / 전압 소스 미터 유닛을 사용하여 출사 광 및 파워 미터 측정 입술에 각기. </li></ol>

<ol>
	<li>Davis, E., Harding, W., Schwartz, R., Coring, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solid+logic+technology:+versatile,+high+performance+microelectronics.">Solid logic technology: versatile, high performance microelectronics.</a> IBM J. Res. Develop. 8, 102-114 (1964).</li><li>Bigas, M., Cabruja, E., Lozano, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bonding+techniques+for+hybrid+active+pixel+sensors+(HAPS).">Bonding techniques for hybrid active pixel sensors (HAPS).</a> Nucl. Instrum. Methods Phys. Res. A. 574 (2), 392-400 (2007).</li><li>Bohandy, J., Kim, B. F., Adrian, F. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal+deposition+from+a+supported+metal+film+using+an+excimer+laser.">Metal deposition from a supported metal film using an excimer laser.</a> J. Appl. Phys. 60 (4), 1538-1539 (1986).</li><li>Kaur, K. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shadowgraphic+studies+of+triazene+assisted+laser-induced+forward+transfer+of+ceramic+thin+films.">Shadowgraphic studies of triazene assisted laser-induced forward transfer of ceramic thin films.</a> J. Appl. Phys. 105 (11), 113119 (2009).</li><li>Boutopoulos, C., Pandis, C., Giannakopoulos, K., Pissis, P., Zergioti, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymer/carbon+nanotube+composite+patterns+via+laser+induced+forward+transfer.">Polymer/carbon nanotube composite patterns via laser induced forward transfer.</a> Appl. Physc. Lett. 96, 041104 (2010).</li><li>Xu, J., Liu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser-assisted+forward+transfer+of+multi-spectral+nanocrystal+quantum+dot+emitters.">Laser-assisted forward transfer of multi-spectral nanocrystal quantum dot emitters.</a> Nanotechnology. 18 (2), 025403 (2007).</li><li>Doraiswamy, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Excimer+laser+forward+transfer+of+mammalian+cells+using+a+novel+triazene+absorbing+layer.">Excimer laser forward transfer of mammalian cells using a novel triazene absorbing layer.</a> Appl. Surf. Sci. 252 (13), 4743-4747 (2006).</li><li>Papazoglou, S., Raptis, Y. S., Chatzandroulis, S., Zergioti, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=I.A+study+on+the+pulsed+laser+printing+of+liquid+phase+exfoliated+graphene+for+organic+electronics.">I.A study on the pulsed laser printing of liquid phase exfoliated graphene for organic electronics.</a> Appl. Phys. A. , (2014).</li><li>Chatzipetrou, M., Tsekenis, G., Tsouti, V., Chatzandroulis, S., Zergioti, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biosensors+by+means+of+the+laser+induced+forward+transfer+technique.">Biosensors by means of the laser induced forward transfer technique.</a> Appl. Surf. Sci. 278, 250-254 (2013).</li><li>Stewart, J. S., Lippert, T., Nagel, M., Nuesch, F., Wokaun, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Red-green-blue+polymer+light-emitting+diode+pixels+printed+by+optimized+laser-induced+forward+transfer.">Red-green-blue polymer light-emitting diode pixels printed by optimized laser-induced forward transfer.</a> Appl. Phys. Lett. 100 (20), 203303 (2012).</li><li>Kaur, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Waveguide+mode+filters+fabricated+using+laser-induced+forward+transfer.">Waveguide mode filters fabricated using laser-induced forward transfer.</a> Opt. Express. 19 (10), 9814-9819 (2011).</li><li>Kuznetsov, A. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser+fabrication+of+large-scale+nanoparticle+arrays+for+sensing+applications.">Laser fabrication of large-scale nanoparticle arrays for sensing applications.</a> ACS Nano. 5 (6), 4843-4849 (2011).</li><li>Rapp, L., Diallo, A. K., Alloncle, A. P., Videlot-Ackermann, C., Fages, F., Delaporte, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulsed-laser+printing+of+organic+thin-film+transistors.">Pulsed-laser printing of organic thin-film transistors.</a> Appl. Phys. Lett. 95 (17), 171109 (2009).</li><li>Bosman, E., Kaur, K. S., Missinne, J., Van Hoe, B., Van Steenberge, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assembly+of+optoelectronics+for+efficient+chip-to-waveguide+coupling.">Assembly of optoelectronics for efficient chip-to-waveguide coupling.</a> , 630-634 (2013).</li><li>Kaur, K. S., Missinne, J., Van Steenberge, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flip-chip+bonding+of+vertical-cavity+surface-emitting+lasers+using+laser-induced+forward+transfer.">Flip-chip bonding of vertical-cavity surface-emitting lasers using laser-induced forward transfer.</a> Appl. Phys. Lett. 104 (6), 061102 (2014).</li><li>Kaur, K. S., al, e. t. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser-induced+forward+transfer+of+focussed+ion+beam+pre-machined+donors.">Laser-induced forward transfer of focussed ion beam pre-machined donors.</a> Appl. Surf. Sci. 257 (15), 6650-6653 (2011).</li></ol>

The authors have nothing to disclose.

본 논문에서는, 우리는 LIFT라는 레이저를 기반으로 직접 쓰기 기술을 사용하여 하나의 VCSEL 칩의 열 압축 플립 칩 본딩을 증명하고있다. LIFT 기술을 이용하여 기판 콘택트 패드 상에 인듐의 마이크로 범프의 인쇄 관련 조립체 제조 단계. 이 열 압착 플립 칩 범프 기판에 VCSEL 칩 본딩 마침내 캡슐화 하였다. LIFT 보조 결합 칩, 전기 광학적, 기계적 신뢰성 그들의 LIV 곡선을 측정?...

레이저 유발 순방향 전송 (LIFT)는 단일 - 단계 패턴 정의 및 미크론 및 서브 미크론 해상도와 물질 전달을위한 다용도의 직접 기록 첨가제의 제조 방법이다. 본 논문에서는, 우리는 칩 스케일에 수직 공동 표면 방출 레이저 (의 VCSEL)의 플립 칩 패키징에 대한 범핑 기술로 LIFT의 사용을보고합니다. 플립 칩은 시스템 패키징 및 전자 및 광전자 (OE) 구성 요소의 통합의 핵심 기술이다. 부품의 고밀도 통합을 달성하기 위해서, 파인 피치 접합이 필수적이다. 파인 피치 접합의 일부 표준 기술에 의해 증명되지만, 유연성, 경제성, 속도, 정확도 및 낮은 가공 온도로 다른 중요한 기능을 함께 결합하는면에서 보이드가되었지만. 이러한 요구 사항을 충족하기 위해, 우리는 OE 성분의 파인 피치 접합 용 LIFT 이용한 열 압착 접합 방법을 설명한다. L에서IFT (도너로 지칭) 인쇄 될 재료의 박막 (담체 라 함) 레이저 투명지지 기판의 한쪽면 상에 증착된다. (1)가이 기술의 기본적인 원리를 도시 한 도표. 충분한 강도의 입사 레이저 펄스는 다음 근접하여 배치 (수신자로 칭함) 또 다른 기판 상에 조사 된 영역의 도너 화소 전송 전달할 필요 추진 동력을 제공 사업자 도너 계면에 집중된다. LIFT 먼저 손상 포토 마스크 (3) 수리를 위해 미크론 크기의 구리 선을 인쇄하는 기술로 Bohandy에 의해 1986 년에보고되었다. 첫 데모 때문에이 기술은 세라믹 4, 탄소 나노 튜브 5, 6 양자점 등 다양한 재료의 패터닝을 제어 및 인쇄, 살아있는 세포 7 그래프 용 마이크로 - 나노 제작 기술에 상당한 관심을 얻고엔 8, 바이오 - 센서 (9), 유기 발광 다이오드 (10), 광전자 부품 (11), 플라즈몬 센서 (12), 유기 전자 (13)와 플립 칩 본딩 (14, 15) 등 다양한 애플리케이션을위한. LIFT는 OE 성분의 플립 칩 장착을위한 단순성, 속도, 유연성, 비용 효율성, 높은 해상도 및 정밀도 등의 기존의 플립 칩 범핑 및 접합 기술에 비해 여러 장점을 제공한다.

<table border="0" cellpadding="0" cellspacing="0" width="663">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Name of Material/ Equipment</td>
			<td style="width:161px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Laser source</td>
			<td style="width:161px;">3D MicroMac (3DMM)</td>
			<td style="width:119px;">2912-295</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Photodetector</td>
			<td style="width:161px;">Newport&#160;</td>
			<td style="width:119px;">818 series</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Source measurement unit</td>
			<td style="width:161px;">Keithley&#160;</td>
			<td style="width:119px;">2401</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Power meter</td>
			<td style="width:161px;">Newport&#160;</td>
			<td style="width:119px;">1930</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Underfill</td>
			<td style="width:161px;">Norlands</td>
			<td style="width:119px;">NOA 86</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">UV lamp</td>
			<td style="width:161px;">Omnicure</td>
			<td style="width:119px;">Series 1000 UV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Probe station</td>
			<td style="width:161px;">Cascade Microtech</td>
			<td style="width:119px;">model 42</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Flip-chip bonder</td>
			<td style="width:161px;">Dr. Tresky</td>
			<td style="width:119px;">T-320 X</td>
			<td></td>
		</tr>
	</tbody>
</table>

laser-induced forward transfer for flip-chip packaging of single dies

플립 칩 (FC) 포장 마이크로 전자 산업에서 고성능, 소형화 및 울트라 고밀도 회로를 실​​현하기위한 핵심 기술이다. 이러한 방법에 칩 및 / 또는 기판은 범핑되고이 두 도전성 범프를 통해 결합된다. 많은 범핑 기술 개발이 집중적 1960 한 이러한 공판 인쇄, 스터드 범핑, 증발과 같은 무전 / 2 FC 전기 도금 기술의 도입으로 조사되었다. 이들 방법은 모두 한 고통이나 비용, 복잡한 처리 단계, 높은 가공 온도, 제조 시간 및 유연성의 가장 중요한 부족 등 해결해야 할 하나 이상의 단점 만든 것을 진행 불구. 본 논문은 레이저 유발 순방향 전송 (LIFT)라고도 간단하고 비용 효율적인 레이저 기반의 범프 형성 기술 3을 증명한다. LIFT 기법 범프를 다양한 재료를 사용하여 수 bRT의 유연성, 높은 속도와 정확도 단일 단계에서 인쇄 한 전자. 또한, LIFT는 초소형 회로를 제조하기위한 중요한 칩 스케일, 아래로 범핑과 결합 할 수 있습니다.

도 7은 다수의 플립 칩 본딩 VCSEL 칩 중 하나에서 기록되었다 LIV 전형적인 곡선을 나타낸다. 공급 업체에 측정 된 광 전력 사이 좋은 경기는 값이 결합 장치 포스트 결합을 성공적으로 기능을 표시 인용했다. 곡선도있어 우선 사후 캡슐화를 기록하고, 그 비교에 (도 7에 도시 된 바와 같이) 밀봉 더 칩의 기능에 영향을했다는 확인되지 않았다. 또한, 플립 칩 본딩의 VCSEL과 베...

Watch this Scientific Journal Video about Laser-induced Forward Transfer for Flip-chip Packaging of Single Dies at JoVE.com

Laser-induced Forward Transfer for Flip-chip Packaging of Single Dies

우리는 광전자 부품의 플립 칩 실장 용 레이저 유발 순방향 전송 (LIFT) 기술의 사용을 입증한다. 이 방법은 간단하고 비용 효과적인 저온, 광전자 응용을위한 고밀도 회로를 실​​현하기위한 칩 크기에 당김 미세 피치 및 접착 용 빠르고 유연한 솔루션을 제공한다.

단일 다이스의 플립 칩 패키징을위한 레이저 유도 앞으로 전송

Flip-chip (FC) packaging is a key technology for realizing high performance, ultra-miniaturized and high-density circuits in the micro-electronics ...

laser-induced-forward-transfer-for-flip-chip-packaging-of-single-dies

Research

JoVE Journal

Engineering

12.2K 조회수.  Ghent University-imec.  우리는 광전자 부품의 플립 칩 실장 용 레이저 유발 순방향 전송 (LIFT) 기술의 사용을 입증한다. 이 방법은 간단하고 비용 효과적인 저온, 광전자 응용을위한 고밀도 회로를 실​​현하기위한 칩 크기에 당김 미세 피치 및 접착 용 빠르고 유연한 솔루션을 제공한다. 

비디오: Laser-induced Forward Transfer for Flip-chip Packaging of Single Dies

Compact Quantum Dots for Single-molecule Imaging

Single-molecule imaging is an important tool for understanding the mechanisms of biomolecular function and for visualizing the spatial and temporal heterogeneity of molecular behaviors that underlie cellular biology 1-4. To image an individual molecule of interest, it is typically conjugated to a fluorescent tag (dye, protein, bead, or quantum dot) and observed with epifluorescence or total internal reflection fluorescence (TIRF) microscopy. While dyes and fluorescent proteins have been the mainstay of fluorescence imaging for decades, their fluorescence is unstable under high photon fluxes necessary to observe individual molecules, yielding only a few seconds of observation before complete loss of signal. Latex beads and dye-labeled beads provide improved signal stability but at the expense of drastically larger hydrodynamic size, which can deleteriously alter the diffusion and behavior of the molecule under study.
Quantum dots (QDs) offer a balance between these two problematic regimes. These nanoparticles are composed of semiconductor materials and can be engineered with a hydrodynamically compact size with exceptional resistance to photodegradation 5. Thus in recent years QDs have been instrumental in enabling long-term observation of complex macromolecular behavior on the single molecule level. However these particles have still been found to exhibit impaired diffusion in crowded molecular environments such as the cellular cytoplasm and the neuronal synaptic cleft, where their sizes are still too large 4,6,7.
Recently we have engineered the cores and surface coatings of QDs for minimized hydrodynamic size, while balancing offsets to colloidal stability, photostability, brightness, and nonspecific binding that have hindered the utility of compact QDs in the past 8,9. The goal of this article is to demonstrate the synthesis, modification, and characterization of these optimized nanocrystals, composed of an alloyed HgxCd1-xSe core coated with an insulating CdyZn1-yS shell, further coated with a multidentate polymer ligand modified with short polyethylene glycol (PEG) chains (Figure 1). Compared with conventional CdSe nanocrystals, HgxCd1-xSe alloys offer greater quantum yields of fluorescence, fluorescence at red and near-infrared wavelengths for enhanced signal-to-noise in cells, and excitation at non-cytotoxic visible wavelengths. Multidentate polymer coatings bind to the nanocrystal surface in a closed and flat conformation to minimize hydrodynamic size, and PEG neutralizes the surface charge to minimize nonspecific binding to cells and biomolecules. The end result is a brightly fluorescent nanocrystal with emission between 550-800 nm and a total hydrodynamic size near 12 nm. This is in the same size range as many soluble globular proteins in cells, and substantially smaller than conventional PEGylated QDs (25-35 nm).

We describe the preparation of colloidal quantum dots with minimized hydrodynamic size for single-molecule fluorescence imaging. Compared to conventional quantum dots, these nanoparticles are similar in size to globular proteins and are optimized for single-molecule brightness, stability against photodegradation, and resistance to nonspecific binding to proteins and cells.

단일 분자 이미징을위한 소형 양자 점

Single-molecule imaging is an important tool for  understanding the mechanisms of biomolecular function and for visualizing the  spatial and temporal ...

연구

공학

Analysis of Contact Interfaces for Single GaN Nanowire Devices

Single GaN nanowire (NW) devices fabricated on SiO2 can exhibit a strong degradation after annealing due to the occurrence of void formation at the contact/SiO2 interface. This void formation can cause cracking and delamination of the metal film, which can increase the resistance or lead to a complete failure of the NW device. In order to address issues associated with void formation, a technique was developed that removes Ni/Au contact metal films from the substrates to allow for the examination and characterization of the contact/substrate and contact/NW interfaces of single GaN NW devices. This procedure determines the degree of adhesion of the contact films to the substrate and NWs and allows for the characterization of the morphology and composition of the contact interface with the substrate and nanowires. This technique is also useful for assessing the amount of residual contamination that remains from the NW suspension and from photolithographic processes on the NW-SiO2 surface prior to metal deposition. The detailed steps of this procedure are presented for the removal of annealed Ni/Au contacts to Mg-doped GaN NWs on a SiO2 substrate.

A technique was developed that removes Ni/Au contact metal films from their substrate to allow for the examination and characterization of the contact/substrate and contact/NW interfaces of single GaN nanowire devices.

단 하나의 GaN 나노 와이어 장치에 대한 문의 인터페이스의 분석

Single GaN nanowire (NW) devices fabricated on SiO2 can exhibit  a strong degradation after annealing due to the  occurrence of void formation at the ...

Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown

In this work, we present time-resolved measurements of atomic and diatomic spectra following laser-induced optical breakdown. A typical LIBS arrangement is used. Here we operate a Nd:YAG laser at a frequency of 10 Hz at the fundamental wavelength of 1,064 nm. The 14 nsec pulses with anenergy of 190 mJ/pulse are focused to a 50 &#181;m spot size to generate a plasma from optical breakdown or laser ablation in air. The microplasma is imaged onto the entrance slit of a 0.6 m spectrometer, and spectra are recorded using an 1,800 grooves/mm grating an intensified linear diode array and optical multichannel analyzer (OMA) or an ICCD. Of interest are Stark-broadened atomic lines of the hydrogen Balmer series to infer electron density. We also elaborate on temperature measurements from diatomic emission spectra of aluminum monoxide (AlO), carbon (C2), cyanogen (CN), and titanium monoxide (TiO).
The experimental procedures include wavelength and sensitivity calibrations. Analysis of the recorded molecular spectra is accomplished by the fitting of data with tabulated line strengths. Furthermore, Monte-Carlo type simulations are performed to estimate the error margins. Time-resolved measurements are essential for the transient plasma commonly encountered in LIBS.

Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown

Time-resolved atomic and diatomic molecular species are measured using LIBS. The spectra are collected at various time delays following the generation of optical breakdown plasma with Nd:YAG laser radiation&#160;and are analyzed to infer electron density and temperature.

측정 및 수소 원자와 이원자 분자 무조건, C 분석<sub&gt; 2</sub&gt;, CN, 및 티오 스펙트럼 뒤에 오는 레이저 광에 의한 고장

In this work, we present time-resolved measurements of atomic and diatomic spectra following laser-induced optical breakdown. A typical LIBS arrangement ...

Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle's Mapping and Quantification in Organ Tissue

Emission spectroscopy of laser-induced plasma was applied to elemental analysis of biological samples. Laser-induced breakdown spectroscopy (LIBS) performed on thin sections of rodent tissues: kidneys and tumor, allows the detection of inorganic elements such as (i) Na, Ca, Cu, Mg, P, and Fe, naturally present in the body and (ii) Si and Gd, detected after the injection of gadolinium-based nanoparticles. The animals were euthanized 1&#160;to 24 hr&#160;after intravenous injection of particles. A two-dimensional scan of the sample, performed using a motorized micrometric 3D-stage, allowed the infrared laser beam exploring the surface with a lateral resolution less than 100 &#956;m. Quantitative chemical images of Gd element inside the organ were obtained with sub-mM sensitivity. LIBS offers a simple and robust method to study the distribution of inorganic materials without any specific labeling. Moreover, the compatibility of the setup with standard optical microscopy emphasizes its potential to provide multiple images of the same biological tissue with different types of response:&#160;elemental, molecular, or cellular.

Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle&#039;s Mapping and Quantification in Organ Tissue

Laser-induced breakdown spectroscopy performed on thin organ and tumor tissue successfully detected natural elements and artificially injected gadolinium (Gd), issued from Gd-based nanoparticles. Images of chemical elements reached a resolution of 100 &#956;m and quantitative sub-mM sensitivity. The compatibility of the setup with standard optical microscopy emphasizes its potential to provide multiple images of a same biological tissue.

레이저 유도 내역 분광학 : 장기 조직에 나노 입자의 매핑 및 정량을위한 새로운 접근

Emission spectroscopy of laser-induced plasma was applied to elemental analysis of biological samples. Laser-induced breakdown spectroscopy (LIBS) ...

Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping

As mass-produced silicon transistors have reached the nano-scale, their behavior and performances are increasingly affected, and often deteriorated, by quantum mechanical effects such as tunneling through single dopants, scattering via interface defects, and discrete trap charge states. However, progress in silicon technology has shown that these phenomena can be harnessed and exploited for a new class of quantum-based electronics. Among others, multi-layer-gated silicon metal-oxide-semiconductor (MOS) technology can be used to control single charge or spin confined in electrostatically-defined quantum dots (QD). These QD-based devices are an excellent platform for quantum computing applications and, recently, it has been demonstrated that they can also be used as single-electron pumps, which are accurate sources of quantized current for metrological purposes. Here, we discuss in detail the fabrication protocol for silicon MOS QDs which is relevant to both quantum computing and quantum metrology applications. Moreover, we describe characterization methods to test the integrity of the devices after fabrication. Finally, we give a brief description of the measurement set-up used for charge pumping experiments and show representative results of electric current quantization.

The fabrication process and experimental characterization techniques relevant to single-electron pumps based on silicon metal-oxide-semiconductor quantum dots are discussed.

As mass-produced silicon transistors have reached the nano-scale, their behavior and performances are increasingly affected, and often deteriorated, by ...

Integration of Light Trapping Silver Nanostructures in Hydrogenated Microcrystalline Silicon Solar Cells by Transfer Printing

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly known as plasmonic effects, play an important role. Research in this field has, however, been impeded owing to the difficulty of fabricating devices containing the desired functional metal nanostructures. In order to provide a viable strategy to this issue, we herein show a transfer printing-based approach that allows the quick and low-cost integration of designed metal nanostructures with a variety of device architectures, including solar cells. Nanopillar poly(dimethylsiloxane) (PDMS) stamps were fabricated from a commercially available nanohole plastic film as a master mold. On this nanopatterned PDMS stamps, Ag films were deposited, which were then transfer-printed onto block copolymer (binding layer)-coated hydrogenated microcrystalline Si (&#181;c-Si:H) surface to afford ordered Ag nanodisk structures. It was confirmed that the resulting Ag nanodisk-incorporated &#181;c-Si:H solar cells show higher performances compared to a cell without the transfer-printed Ag nanodisks, thanks to plasmonic light trapping effect derived from the Ag nanodisks. Because of the simplicity and versatility, further device application would also be feasible thorough this approach.

A viable transfer printing-based methodology to introduce plasmonic metal nanostructures in solar cells is described. Using nanopillar poly(dimethylsiloxane) stamps, an Ag-based ordered nanodisk array was integrated with standard hydrogenated microcrystalline Si solar cells, which led to improved device performances due to plasmonic light trapping.

전송 인쇄하여 수소 첨가 미세 결정 실리콘 태양 전지에 빛 트래핑 실버 나노 구조의 통합

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly ...

Laser-induced Forward Transfer of Ag Nanopaste

Over the past decade, there has been much development of non-lithographic methods1-3 for printing metallic inks or other functional materials. Many of these processes such as inkjet3 and laser-induced forward transfer (LIFT)4 have become increasingly popular as interest in printable electronics and maskless patterning has grown. These additive manufacturing processes are inexpensive, environmentally friendly, and well suited for rapid prototyping, when compared to more traditional semiconductor processing techniques. While most direct-write processes are confined to two-dimensional structures and cannot handle materials with high viscosity (particularly inkjet), LIFT can transcend both constraints if performed properly. Congruent transfer of three dimensional pixels (called voxels), also referred to as laser decal transfer (LDT)5-9, has recently been demonstrated with the LIFT technique using highly viscous Ag nanopastes to fabricate freestanding interconnects, complex voxel shapes, and high-aspect-ratio structures. In this paper, we demonstrate a simple yet versatile process for fabricating a variety of micro- and macroscale Ag structures. Structures include simple shapes for patterning electrical contacts, bridging and cantilever structures, high-aspect-ratio structures, and single-shot, large area transfers using a commercial digital micromirror device (DMD) chip.

We demonstrate the use of the Laser-induced forward transfer technique (LIFT) for the printing of high-viscosity Ag paste. This technique offers a simple, low temperature, robust process for non-lithographically printing microscale 2D and 3D structures.

의 Ag Nanopaste의 레이저 유도 앞으로 전송

Over the past decade, there has been much development of non-lithographic methods1-3 for printing metallic inks or other functional materials. Many of ...

Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation

We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using femtosecond laser-induced ablation. We show that thousands of periodic nano-craters are fabricated on an optical nanofiber by irradiating with just a single femtosecond laser pulse. For a typical sample, periodic nano-craters with a period of 350 nm and with diameter gradually varying from 50 - 250 nm over a length of 1 mm are fabricated on a nanofiber with diameter around 450 - 550 nm. A key aspect of such a nanofabrication is that the nanofiber itself acts as a cylindrical lens and focuses the femtosecond laser beam on its shadow surface. Moreover, the single-shot fabrication makes it immune to mechanical instabilities and other fabrication imperfections. Such periodic nano-craters on nanofiber, act as a 1-D PhC and enable strong and broadband reflection while maintaining the high transmission out of the stopband. We also present a method to control the profile of the nano-crater array to fabricate apodized and defect-induced PhC cavities on the nanofiber. The strong confinement of the field, both transverse and longitudinal, in the nanofiber-based PhC cavities and the efficient integration to the fiber networks, may open new possibilities for nanophotonic applications and quantum information science.

We present a protocol for fabricating 1-D photonic crystal cavities on subwavelength diameter silica fibers (optical nanofibers) using femtosecond laser-induced ablation.

펨토초 레이저에 의한 절제를 사용하여 나노 섬유에 1-D 광자 크리스탈 캐비티의 제작

We present a protocol for fabricating 1-D Photonic Crystal (PhC) cavities on subwavelength-diameter tapered optical fibers, optical nanofibers, using ...

Scanning Light Scattering Profiler (SLPS) Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light scattering from intraocular lenses (IOLs) using goniophotometer principles. This protocol describes the SLSP platform and how it employs a 360&#176; rotational photodetector sensor that is scanned around an IOL sample while recording the intensity and location of scattered light as it passes through the IOL medium. The SLSP platform can be used to predict, non-clinically, the propensity for current and novel IOL designs and materials to induce light scatter. Non-clinical evaluation of light scattering properties of IOLs can significantly reduce the number of patient complaints related to unwanted glare, glistening, optical defects, poor image quality, and other phenomena associated with the unintended light scattering. Future studies should be conducted to correlate SLSP data with clinical results to help identify which measured light scatter is most problematic for patients that have undergone cataract surgery subsequent to IOL implantation.

Scanning Light Scattering Profiler SLPS Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses

This protocol describes the scanning light scattering profiler (SLSP) that enables the full-angle quantitative evaluation of forward and backward scattering of light from intraocular lenses (IOLs) using goniophotometer principles.

SLPS (Scanning Profiling Profiler) 기반 방법론으로 안구 내 렌즈의 전방 및 후방 산란을 정량적으로 평가

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light ...

All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics

The miniaturization of semiconductor devices to scales where small numbers of dopants can control device properties requires the development of new techniques capable of characterizing their dynamics. Investigating single dopants requires sub-nanometer spatial resolution, which motivates the use of scanning tunneling microscopy (STM). However, conventional STM is limited to millisecond temporal resolution. Several methods have been developed to overcome this shortcoming, including all-electronic time-resolved STM, which is used in this study to examine dopant dynamics in silicon with nanosecond resolution. The methods presented here are widely accessible and allow for local measurement of a wide variety of dynamics at the atomic scale. A novel time-resolved scanning tunneling spectroscopy technique is presented and used to efficiently search for dynamics.

We demonstrate an all-electronic method to observe nanosecond-resolved charge dynamics of dopant atoms in silicon with a scanning tunneling microscope.

모든 전자 나노초 해결 주사 터널링 현미경: 촉진 단일 불순물 충전 역학 조사

The miniaturization of semiconductor devices to scales where small numbers of dopants can control device properties requires the development of new ...