二维材料红外光电探测器中介电衬底表面态及其界面散射研究

Owing to the unique dimensional effect, quantum effect, optoelectronic properties, two dimensional (2D) materials can be considered as the focal plane material which is used to fabricate high performance infrared photodetectors at room temperature with the characteristics of lightweight, low dark current, high photoresponsivity, to circumvent the limitation of 77K working temperature for conventional infrared photodetectors. However, based on the fabrication technology of device substrate, the surface states of substrate including in surface defects, surface traps, surface dangling bonds, and the interface scattering problems between substrate and 2D materials including in phonon scattering, impurity scattering, provide largely development space for photodetecting performance. In this project, we will use Self-assembled monolayer (SAMs) technique to fabricate monomolecular layer on the substrate to avoid the contact between substrate and 2D materials, to overcome surface states and interface scattering, for achieving the fabrication of high performance BP and b-AsP photodetectors working at room temperature. By virtue of electrical property testing system and micro area photocurrent scanning system, and combined with the theory model of recombination and transport of carriers at interface of 2D materials and substrate, we will deeply study the influence of the photodetecting performance caused by surface states and interface scattering, to provide the experimental and theoretical guidance for substrate optimization to fabricate high performance infrared 2D materials photodetectors working at room temperature.

二维材料以其独特的尺寸效应、量子效应、光电效应等特性，成为制备具有轻量化、低暗电流、高响应度、室温红外探测等高性能红外光电探测器的焦平面材料，以解决当前传统红外光电探测器必须处于近77K低温下工作的条件限制。但由于器件衬底表面缺陷、表面陷阱、悬挂键等表面态，以及衬底与二维材料间界面的声子散射、杂质散射问题，使得探测器性能存在较大的改进空间。本项目拟采用单分子层自组装技术（SAMs）对衬底表面实现单分子层修饰，来避免衬底与二维材料的接触，旨在利用单分子层修饰改善衬底表面态及界面散射问题，研制出实现室温高性能基于黑磷（BP）和黑砷磷（b-AsP）二维材料的红外光电探测器。利用电学物性测试系统以及微区光电流扫描系统技术，并结合二维材料界面载流子复合、输运理论模型，深入研究衬底表面态及界面散射对探测器性能的影响，为实现室温高性能二维材料红外光电探测器的研制提供衬底优化方面的实验及理论指导。

二维材料红外光电探测器中介电衬底表面态及其界面散射研究（61704061），拟采用单分子层自组装技术（SAMs）对衬底表面实现单分子层修饰，为避免衬底与二维材料的接触，旨在利用单分子层解决衬底表面态及界面散射问题，研制出实现室温高性能基于二维材料的红外光电探测器。 .经历了三年的研究，我们已经研制出室温高性能二维半导体的红外光电探测器，在1.55um波段，其光电响应率R＞50 A/W，探测率D*＞1×1010 Jones；在4um波段，其光电响应率R＞1 A/W，探测率D*＞1×109 Jones。针对介电衬底对器件性能的性能影响研究，我们优化了单分子层的OTMS和DTMS介电衬底的制备参数，结合实验结果得出结论：高表面能的介电衬底可以减少器件的光生载流子在输运过程中声子散射、缺陷散射，有助于器件的电学特性，减少光生空穴与电子的复合，提高光生电流。但是也大大增加了器件制备中二维半导体转移到器件衬底上的难度，降低器件制备良率。针对此问题，我们开发PPC作为转移工艺过程中的牺牲材料，可以提高器件制备良率。 .项目支撑的相关研究工作已经发表在一些高水平杂志上，包括：Applied Materials Today, Advanced Materials, Nano Research, ACS Nano，Nature Communcations等。