Vertical MoTe₂/Ge Heterojunction Photodiode for 1550-nm Near-Infrared Photodetection
Wenyu Lei, Xiaokun Wen, Li Yang, Pengzhen Zhang, Guowei Cao, Fuwei Zhuge, Youwei Zhang, Haixin Chang, Wenfeng Zhang
Abstract
We demonstrate a vertical MoTe2/Ge heterojunction near-infrared photodiode that exhibits a low dark current density, an improved capacity of weak optical signal detection with a peak detectivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.15\times 10^{{11}}$ </tex-math></inline-formula> Jones under a light density of 1 mW cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{2}}$ </tex-math></inline-formula> , and a response speed with a rise/fall time of 8/6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> operating at a 1550-nm light illumination. The device performance characteristics indicate that MoTe2/Ge heterojunction photodiode is promising for the potential practical application of photodetection at 1550 nm.