Yu Mengxuan, Yang Ji, Zhang Xingchen, Yuan Mohan, Zhang Jianbing, Gao Liang, Tang Jiang, Lan Xinzheng
School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China.
Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, P. R. China.
Adv Mater. 2024 Jul;36(27):e2311830. doi: 10.1002/adma.202311830. Epub 2024 Apr 29.
Colloidal Quantum Dots (CQDs) of mercury telluride (HgTe) hold particular appeal for infrared photodetection due to their widely tunable infrared absorption and good compatibility with silicon electronics. While advances in surface chemistry have led to improved CQD solids, the chemical stability of HgTe material is not fully emphasized. In this study, it is aimed to address this issue and identifies a Se-stabilization strategy based on the surface coating of Se on HgTe CQDs via engineering in the precursor reactivity. The presence of Se-coating enables HgTe CQDs with improved colloidal stability, passivation, and enhanced degree of freedom in doping tuning. This enables the construction of optimized p-i-n HgTe CQD infrared photodetectors with an ultra-low dark current 3.26 × 10 A cm⁻ at -0.4 V and room-temperature specific detectivity of 5.17 × 10 Jones at wavelength ≈2 um, approximately one order of magnitude improvement compared to that of the control device. The stabilizing effect of Se is well preserved in the thin film state, contributing to much improved device stability. The in-synthesis Se-stabilization strategy highlights the importance of the chemical stability of materials for the construction of semiconductor-grade CQD solids and may have important implications for other high-performance CQD optoelectronic devices.
碲化汞（HgTe）胶体量子点（CQD）因其广泛可调谐的红外吸收以及与硅电子器件的良好兼容性，在红外光电探测方面具有特殊的吸引力。虽然表面化学的进展已使CQD固体得到改进，但HgTe材料的化学稳定性并未得到充分重视。在本研究中，旨在解决这一问题，并通过在前体反应性方面进行工程设计，确定一种基于在HgTe CQD表面包覆硒（Se）的硒稳定策略。硒包覆的存在使HgTe CQD具有更好的胶体稳定性、钝化效果以及在掺杂调谐方面更高的自由度。这使得能够构建优化的p-i-n HgTe CQD红外光电探测器，在-0.4 V时具有3.26×10 A cm⁻的超低暗电流，在波长≈2μm时室温比探测率为5.17×10 Jones，与对照器件相比提高了约一个数量级。硒的稳定作用在薄膜状态下得到了很好的保持，有助于大大提高器件稳定性。合成过程中的硒稳定策略突出了材料化学稳定性对于构建半导体级CQD固体的重要性，并且可能对其他高性能CQD光电器件具有重要意义。
