InGaAs光电晶体管面阵/OLED结构上转换红外成像器件研制

Infrared detection has many important applications in military and civilian areas. The upconversion device can convert infrared light to visible light, and combine with CCD to capture Infrared imaging. Recently, the single-element infrared upconverter has high efficiency, while the imaging device has low efficiency. In previous work, we have fabricated InGaAs detectors/OLED integrated upconverter. We also optimized InGaAs phototransistor, the gain of InGaAs phototransistor can be up to 400 or higher. In this case, we propose that a two dimensional InGaAs heterojunction phototransistors array integrated with a large-area single-element OLED layer to be pixelated infrared imaging device. The continuous OLED layers on top of the heterojunction phototransistors pixel array are expected not to cause significant lateral current spreading due to their poor lateral electrical conductivity. Each isolated element is an active Infrared upconverter, which can convert 1.5 µm light to visible light. Firstly, we will further optimize the InGaAs phototransistors including layer thickness and doping level to improve upconversion efficiency up to 1500%. To improve the performance of InGaAs phototransistors, new strategies in interfacial engineering, including TCAD simulation and c-AFM will be applied to investigate the characteristics of hetero-interface and enhance the current injection efficiency. Secondly, we will fabricate InGaAs phototransistors array/OLED imaging device, including 256×256 and larger pixels. Finally, we can get lost-cost, high efficiency infrared imaging devices.

红外探测在军事和民用领域都具有非常重要的作用，上转换器件可以将红外光转换为可见光，进而与硅CCD组合实现红外探测。目前红外上转换器件研究面临着单元器件高转换效率，成像器件低转换效率的现状。前期工作中，我们已经研制了基于InGaAs红外探测器/OLED集成结构上转换器件，我们还通过器件优化把InGaAs光电晶体管电流增益提升到400以上。本项目我们提出InGaAs光电晶体管面阵/OLED集成方案，研制高转换效率红外上转换成像器件：该器件由一个二维InGaAs光电晶体管面阵与整层OLED集成而形成，每一个独立的上转换器件都是一个有效的像元，能够将1.5微米的近红外光转换为可见光。本项目将首先利用晶体管性优化提升InGaAs光电晶体管/OLED单元器件上转换效率(>1500%)；在此基础上，研制InGaAs光电晶体管面阵/OLED近红外上转换成像器件，像素高于256×256，实现高性能红外成像。

高性能的近红外成像器件在军事和民用领域都有非常重要的应用。本项目围绕红外上转换成像器件的研制，首先研究了高性能的InGaAs探测器，建立了一个基于InGaAs/InAlAs材料的吸收、渐变、电荷、倍增分离型(SAGCM)雪崩光电二极管模型，研究了器件的线性度和与之相互折衷的击穿特性、增益和响应度等。通过引入深能级缺陷的模型，提高了InGaAs/InAlAs光电二极管C-V特性的拟合度。建立了一个InAlAsSb SACM型雪崩光电二极管的仿真模型，通过改变其电荷层和倍增层的掺杂浓度和厚度来研究其穿通电压、雪崩击穿电压和增益等特性。其次在新型探测器研制方面，研究了一种双层石墨烯/砷化镓肖特基结近红外光电探测器。通过在双层石墨烯和砷化镓之间插入氧化铝钝化层来降低器件的暗电流。此外，在双层石墨烯表面旋涂一层银纳米颗粒，利用银纳米颗粒的表面等离子体效应增强器件的光电流。在Si基探测器方面，通过等离子体刻蚀在Si基光电探测器表面制备规则有序的微结构阵列，或者插入石墨烯层，可以与Si集成形成范德华异质结，提升Si探测器的近红外波段探测率。最后在红外上转换器件研制上，研究了InGaAs/InAlAs探测器与OLED集成以及InGaAs/InP探测器与OLED集成, 通过优化InGaAs/InP探测器结构以及与磷光OLED集成，提升上转换效率。为了拓展红外上转换器件的集成方式，我们也研究了Si基探测器与OLED的集成，得到基于Si基探测器/OLED结构的新型红外上转换器件，包括像素化器件，以及无像素器件。本项目推动了基于上转换红外器件的新型红外成像技术的发展。