Abstract. The photoresponse mechanism of graphene/InSb heterojunction middle-wavelength infrared (MWIR) photodetectors was investigated. The devices comprised a graphene/InSb heterojunction as a carrier-injection region and an insulator region of graphene on tetraethyl orthosilicate (TEOS) for photogating. The MWIR photoresponse was significantly amplified with an increase in the graphene/TEOS cross-sectional area by covering the entire detector with graphene. The graphene-channel dependence of the MWIR photoresponse indicated that the graphene carrier density was modulated by photocarrier accumulation at the TEOS/InSb boundary, resulting in photogating. The dark current of the devices was suppressed by a decrease in the graphene/InSb carrier-injection region and the formation of the heterojunction using an n-type InSb substrate. The results indicate that photocarrier transportation was dominated by the formation of a Schottky barrier at the interface of the graphene/InSb heterojunction and a Fermi-level shift under bias application. The high-responsivity and low-dark-current photoresponse mechanism was attributed to the graphene/InSb heterojunction diode behavior and the photogating effect. The devices combining the aforementioned features had a noise equivalent power of 0.43 pW / Hz1/2. The results obtained in our study will contribute to the development of high-performance graphene-based IR image sensors.

中文翻译：

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石墨烯/InSb异质结中波长红外光电探测器的载流子密度调制和光载流子传输

摘要。研究了石墨烯/InSb异质结中波长红外（MWIR）光电探测器的光响应机制。这些器件包括一个石墨烯/InSb 异质结作为载流子注入区和一个位于原硅酸四乙酯 (TEOS) 上的用于光选通的石墨烯绝缘体区。通过用石墨烯覆盖整个探测器，随着石墨烯/TEOS 横截面积的增加，MWIR 光响应显着放大。MWIR 光响应的石墨烯通道依赖性表明石墨烯载流子密度受 TEOS/InSb 边界处光载流子积累的调节，导致光门控。石墨烯/InSb 载流子注入区的减少和使用 n 型 InSb 衬底的异质结的形成抑制了器件的暗电流。结果表明，光载流子传输主要由石墨烯/InSb 异质结界面处的肖特基势垒形成和偏置施加下的费米能级位移所主导。高响应性和低暗电流光响应机制归因于石墨烯/ InSb 异质结二极管的行为和光门控效应。结合上述特征的设备的噪声等效功率为 0.43 pW/Hz1/2。我们研究中获得的结果将有助于开发基于石墨烯的高性能红外图像传感器。高响应性和低暗电流光响应机制归因于石墨烯/ InSb 异质结二极管的行为和光门控效应。结合上述特征的设备的噪声等效功率为 0.43 pW/Hz1/2。我们研究中获得的结果将有助于开发基于石墨烯的高性能红外图像传感器。高响应性和低暗电流光响应机制归因于石墨烯/ InSb 异质结二极管的行为和光门控效应。结合上述特征的设备的噪声等效功率为 0.43 pW/Hz1/2。我们研究中获得的结果将有助于开发基于石墨烯的高性能红外图像传感器。