arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.14721cond-mat.mes-hallcond-mat.mtrl-sci
收藏

陷阱在薄In-Se光电探测器光电流产生机制中的作用

The role of traps in the photocurrent generation mechanism in thin In-Se photodetectors

Qinghua Zhao, Wei Wang, Felix Carrascoso-Plana, Wanqi Jie, Tao Wang, Andres Castellanos-Gomez, Riccardo Frisenda

摘要:

硒化铟(InSe)薄膜由于其优异的电输运性能和光电性能,近年来在二维半导体材料领域引起了广泛的关注。然而,在薄InSe光电探测器中光电流产生背后的机制仍然难以捉摸。在这里,我们提出了一组实验,旨在解释在文献中报道的薄InSe光电探测器的光响应度值的强散射。通过对在不同环境条件下工作的薄InSe基光电探测器进行光电测量,我们发现在这种材料中,光响应度、响应时间和光电流功率依赖性强烈相关。这一观察结果表明,光控效应起着重要的作用,薄的InSe薄片,它是在原始InSe器件的超高光响应性的主导机制。此外,当暴露的原始的InSe光电探测器的周围环境中,我们观察到一个快速和不可逆的变化的光响应,与减少的光响应伴随着操作速度的增加。我们属性这种光电探测器性能的变化(在大气中暴露)的密度降低的陷阱中存在的In Se,由于钝化的硒空位由大气中的氧物种。这种钝化伴随着InSe费米能级的下移和费米能级钉扎的减少,这导致Au和InSe之间的肖特基势垒的增加。我们的研究揭示了由缺陷引起的陷阱在定制基于2D材料的器件的特性中的重要作用,并提供了一种可控的路线来设计和功能化薄InSe光电探测器,以实现具有低光响应性或快速操作速度的器件。

英文摘要:

Due to the excellent electrical transport properties and optoelectronic performance, thin indium selenide (InSe) has recently attracted attention in the field of 2D semiconducting materials. However, the mechanism behind the photocurrent generation in thin InSe photodetectors remains elusive. Here, we present a set of experiments aimed at explaining the strong scattering in the photoresponsivity values reported in the literature for thin InSe photodetectors. By performing optoelectronic measurements on thin InSe-based photodetectors operated under different environmental conditions we find that the photoresponsivity, the response time and the photocurrent power dependency are strongly correlated in this material. This observation indicates that the photogating effect plays an imporant role for thin InSe flakes, and it is the dominant mechanism in the ultra-high photoresponsivity of pristine InSe devices. In addition, when exposing the pristine InSe photodetectors to the ambient environment we observe a fast and irreversible change in the photoresponse, with a decrease in the photoresponsivity accompanied by an increase of the operating speed. We attribute this photodetector performance change (upon atmospheric exposure) to the decrease in the density of the traps present in InSe, due to the passivation of selenium vacancies by atmospheric oxygen species. This passivation is accompanied by a downward shift of the InSe Fermi level and by a decrease of the Fermi level pinning, which leads to an increase of the Schottky barrier between Au and InSe. Our study reveals the important role of traps induced by defects in tailoring the properties of devices based on 2D materials and offers a controllable route to design and functionalize thin InSe photodetectors to realize devices with either ultrahigh photoresposivity or fast operation speed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑