Defects-induced oxidation of two-dimensional β-In2S3 and its optoelectronic properties

Abstract

Two-dimensional (2D) β-In 2 S 3 with a natural defective structure is a promising semiconductor for electronic and optoelectronic applications. Herein, oxidation of 2D β-In 2 S 3 is investigated by photoluminescence, Raman scattering, and X-ray photoelectron spectroscopy studies for understanding its optoelectronic properties. Our results show that the intrinsic structural defects of sulfur vacancies induce the oxidation of β-In 2 S 3 , which can act as active sites to adsorb oxygen in air. Oxygen atoms react with indium atoms to form an inner layer of In 2 S 3-3x O 3x and outer layer of In 2 O 3 , resulting in intriguing optical properties over the exposure time to air. Moreover, the energy level diagram based on the defect-mediated oxidation process is presented. Additionally, the effect of oxidation under ambient air on β-In 2 S 3 based photodetector and field effect transistor is investigated. Our study provides an in-depth understanding of the oxidation process of 2D β-In 2 S 3 and paves a fundamental step for its potential applications in future electronics and optoelectronics. • Defects can act as active sites for molecule adsorption in air to induce oxidation. • β-In 2 S 3 is a typical natural defective crystal. • Photoluminescence of two-dimensional β-In 2 S 3 varies as the exposure time to air. • Performance of photoresponsivity degrades while mobility increases after oxidation.