Kim Jaehyun, Kwon Sung Min, Jo Chanho, Heo Jae-Sang, Kim Won Bin, Jung Hyun Suk, Kim Yong-Hoon, Kim Myung-Gil, Park Sung Kyu
Displays and Devices Research Laboratory School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 06974, Korea.
Department of Medicine, University of Connecticut School of Medicine, Farmington 06030, Connecticut, United States.
ACS Appl Mater Interfaces. 2020 Apr 8;12(14):16620-16629. doi: 10.1021/acsami.0c01176. Epub 2020 Mar 25.
Quantum dot (QD)-based optoelectronics have received great interest for versatile applications because of their excellent photosensitivity, facile solution processability, and the wide range of band gap tunability. In addition, QD-based hybrid devices, which are combined with various high-mobility semiconductors, have been actively researched to enhance the optoelectronic characteristics and maximize the zero-dimensional structural advantages, such as tunable band gap and high light absorption. However, the difficulty of highly efficient charge transfer between QDs and the semiconductors and the lack of systematic analysis for the interfaces have impeded the fidelity of this platform, resulting in complex device architectures and unsatisfactory device performance. Here, we report ultrahigh detective phototransistors with highly efficient photo-induced charge separation using a SnS-capped CdSe QD/amorphous oxide semiconductor (AOS) hybrid structure. The photo-induced electron transfer characteristics at the interface of the two materials were comprehensively investigated with an array of electrochemical and spectroscopic analyses. In particular, photocurrent imaging microscopy revealed that interface engineering in QD/AOS with chelating chalcometallate ligands causes efficient charge transfer, resulting in photovoltaic-dominated responses over the whole channel area. On the other hand, monodentate ligand-incorporated QD/AOS-based devices typically exhibit limited charge transfer with atomic vibration, showing photo-thermoelectric-dominated responses in the drain electrode area.
基于量子点（QD）的光电器件因其优异的光敏性、简便的溶液可加工性和宽范围的带隙可调性而在多种应用中备受关注。此外，与各种高迁移率半导体相结合的基于量子点的混合器件也得到了积极研究，以增强光电子特性并最大化零维结构优势，如可调带隙和高光吸收。然而，量子点与半导体之间高效电荷转移的困难以及对界面缺乏系统分析阻碍了该平台的保真度，导致器件架构复杂且器件性能不尽人意。在此，我们报道了一种采用硫化锡包覆的硒化镉量子点/非晶氧化物半导体（AOS）混合结构的具有高效光致电荷分离的超高探测光晶体管。通过一系列电化学和光谱分析全面研究了两种材料界面处的光致电子转移特性。特别是，光电流成像显微镜显示，在量子点/非晶氧化物半导体中使用螯合硫属金属酸盐配体进行界面工程可实现高效电荷转移，从而在整个沟道区域产生以光伏为主的响应。另一方面，基于单齿配体掺入的量子点/非晶氧化物半导体的器件通常表现出因原子振动而受限的电荷转移，在漏极区域呈现以光热电为主的响应。
