In this paper, a novel InGaZnO (IGZO) Infrared (IR) thin-film Phototransistor (Photo-TFT) consisting of Germanium capping layer (Ge-CL) and high-k dielectric material is proposed and numerically investigated. The role of introducing Ge-CL/IGZO heterojunction and high-k dielectric such as HfO₂, ZrO₂, Ta₂O₅ and TiO₂ in achieving the dual benefit of IR photodetection ability and reduced dark noise effects is demonstrated. It is found that the proposed Ge-CL/IGZO Photo-TFT with appropriate gate oxide material can offer high detectivity of 2.3 × 10¹⁴ Jones, superior current ratio exceeding 200 dB and high IR responsivity of 4.1 × 10² A/W. These enhancements are attributed to a mixture of two effects; firstly, the introduction of p-type Ge-CL leads to form a p-n junction with IGZO, thus enhancing the separation and transfer mechanisms of photo-induced electron/hole pairs. Secondly, the use of high-k dielectric materials enables better control of the channel conductivity, allowing reduced power consumption. Therefore, we believe that the use of Ge-CL with suitable high-k dielectric material pinpoints a new pathway to design high IR photoresponse sensors based on cost-effective IGZO TFT building block, which makes it potential alternative for high-performance optoelectronic systems.

在本文中，提出并数值研究了一种由锗覆盖层 (Ge-CL) 和高 k 介电材料组成的新型 InGaZnO (IGZO) 红外 (IR) 薄膜光电晶体管 (Photo-TFT)。证明了引入 Ge-CL/IGZO 异质结和高 k 电介质（如 HfO ₂、ZrO ₂、Ta ₂ O ₅和 TiO _{2 ）}在实现红外光电探测能力和降低暗噪声效应的双重好处中的作用。结果表明，所提出的具有适当栅极氧化物材料的 Ge-CL/IGZO Photo-TFT 可提供 2.3 × 10 ¹⁴ Jones 的高探测率、超过 200 dB 的优异电流比和 4.1 × 10 ^{2 的}高红外响应率秋/冬。这些增强归因于两种效果的混合；首先，p型Ge-CL的引入导致与IGZO形成pn结，从而增强了光生电子/空穴对的分离和转移机制。其次，使用高 k 介电材料可以更好地控制沟道电导率，从而降低功耗。因此，我们相信使用 Ge-CL 和合适的高 k 介电材料为设计基于具有成本效益的 IGZO TFT 构建块的高红外光响应传感器指明了一条新途径，这使其成为高性能光电系统的潜在替代品。