Song Yanan, Hu Qianqian, Zhao Xiao, Gnatyuk Volodymyr, Meng Gang, Huang Changbao, Wu Haixin, Ni Youbao, Wang Shimao
Advanced Laser Technology Laboratory of Anhui Province, Anhui Provincial Key Laboratory of Photonic Devices and Materials, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, People's Republic of China.
University of Science and Technology of China, Hefei 230026, People's Republic of China.
ACS Appl Mater Interfaces. 2024 Dec 25;16(51):70634-70643. doi: 10.1021/acsami.4c12403. Epub 2024 Dec 11.
When creating a Schottky contact to suppress the leakage current of semiconductor γ-ray detectors and improve their energy resolution, it is successfully employed the fact that the formation of a Schottky barrier is determined not only by the difference in the electrode and semiconductor work functions but also affected by the semiconductor surface state. Oxygen plasma (OP) treatment has been used to modify the surface states of CdSe single crystals (SCs) prior to the Au electrode deposition, thereby creating a Schottky contact at the metal-semiconductor interface. The -type Schottky contact formation has been confirmed by the - characteristics and ultraviolet photoelectron spectroscopy analysis. X-ray photoelectron spectroscopy has shown that the stoichiometric state of the CdSe SC surface changes from a Cd-deficient (untreated surface) to a near-ideal stoichiometric (OP-treated surface). In addition, a newly formed CdSeO component has been revealed, which is beneficial for suppressing the surface leakage current. The Au/CdSe/Au radiation detector with the single-sided OP-treated surface (Schottky diode) exhibits a higher energy resolution of (23.93 ± 0.89)% for Am 59.5 keV γ-rays compared to that of the detectors without surface treatment ((44.66 ± 2.25)%). The energy resolution of the champion CdSe-based Schottky diode type γ-ray detector for Am 59.5 keV γ-rays can reach 22.72%.
在创建肖特基接触以抑制半导体γ射线探测器的漏电流并提高其能量分辨率时，成功利用了这样一个事实：肖特基势垒的形成不仅取决于电极和半导体功函数的差异，还受半导体表面态的影响。在沉积金电极之前，已使用氧等离子体（OP）处理来改变CdSe单晶（SCs）的表面态，从而在金属 - 半导体界面处形成肖特基接触。通过 - 特性和紫外光电子能谱分析证实了 - 型肖特基接触的形成。X射线光电子能谱表明，CdSe SC表面的化学计量状态从缺镉（未处理表面）变为接近理想化学计量（OP处理表面）。此外，还发现了一种新形成的CdSeO成分，这有利于抑制表面漏电流。与未进行表面处理的探测器（（44.66 ± 2.25）%）相比，具有单面OP处理表面的Au/CdSe/Au辐射探测器对Am 59.5 keV γ射线表现出更高的能量分辨率，为（23.93 ± 0.89）%。用于Am 59.5 keV γ射线的最佳基于CdSe的肖特基二极管型γ射线探测器的能量分辨率可达22.72%。
