Negative photoresponse in Ti3C2Tx MXene monolayers

Abstract

Two-dimensional transition metal carbides, nitrides, and carbonitrides, collectively known as MXenes, are finding numerous applications in many different areas, including optoelectronics and photonics, but there is limited information about their intrinsic photoresponse. In this study, we investigated the visible and near-infrared range photoresponse of Ti3C2Tx, the most popular MXene material to date. The electrical measurements were performed on devices based on individual monolayer Ti3C2Tx MXene flakes, which were characterized by a variety of microscopic and spectroscopic methods. For MXene devices with different electrode layouts, the current reproducibly decreased under illumination with either white light or lasers with different wavelengths in the visible and near-infrared region, thus demonstrating a negative photoresponse. The understanding of the intrinsic photoresponse of Ti3C2Tx should facilitate the optoelectronic and photonic applications of MXenes.

Keywords

• mxenes
• negative photoresponse
• ti3c2tx
• titanium carbide