Evolution of the Electronic Band Structure and Efficient Photo-Detection in Atomic Layers of InSe

Atomic layers of two-dimensional (2D) materials have recently been the focus of extensive research. This follows from the footsteps of graphene, which has shown great potential for ultrathin optoelectronic devices. In this paper, we present a comprehensive study on the synthesis, characterization, and thin film photodetector application of atomic layers of InSe. Correlation between resonance Raman spectroscopy and photoconductivity measurements allows us to systematically track the evolution of the electronic band structure of 2D InSe as its thickness approaches few atomic layers. Analysis of photoconductivity spectra suggests that few-layered InSe has an indirect band gap of 1.4 eV, which is 200 meV higher…