MXene-GaN van der Waals metal-semiconductor junctions for high performance multiple quantum well photodetectors

摘要

A MXene-GaN-MXene based multiple quantum well photodetector was prepared on patterned sapphire substrate by facile drop casting.The use of MXene electrodes improves the responsivity and reduces dark current,compared with traditional Metal-Semiconductor-Metal(MSM)photodetectors using Cr/Au electrodes.Dark current of the device using MXene-GaN van der Waals junctions is reduced by three orders of magnitude and its noise spectral intensity shows distinct improvement compared with the traditional Cr/Au–GaN–Cr/Au MSM photodetector.The improved device performance is attributed to low-defect MXene-GaN van der Waals interfaces.Thanks to the high quality MXene-GaN interfaces,it is possible to verify that the patterned substrate can locally improve both light extraction and photocurrent collection.The measured responsivity and specific detectivity reach as high as 64.6 A/W and 1.93×1012 Jones,respectively,making it a potential candidate for underwater optical detection and communication.The simple fabrication of MXene-GaN-MXene photodetectors spearheaded the way to high performance photodetection by combining the advantages of emerging 2D MXene materials with the conventional III-V materials.