Chromium Doping Effects on Tuning n- to p- ReSe₂ for Homojunction Device Application

Adzilah Shahna Rosyadi^1*, Ching-Hwa Ho¹

¹Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei City, Taiwan

* Presenter:Adzilah Shahna Rosyadi, email:D10922801@mail.ntust.edu.tw

The ability for tuning the carrier type by doping transition metal into 2D material TMDCs is demanded to create optoelectronic devices. Lattice matching and band alignment were the common issues arisen when constructing heterojunction. In this work, Chromium was doped to replace Re sites in rhenium diselenide crystal grown by CVT method resulting in no change in structure and bandgap confirmed by HRTEM image and thermal-reflectance (TR) measurement at 20K and 300K respectively. The X-ray photoemission spectroscopy (XPS), Hall effect, and temperature-dependent of resistivity measurement construct the energy band diagram to verify Cr ions trapping. Cr⁶⁺ was located in the deep level near Fermi level acting as n-ReSe₂ in lower Cr composition. Meanwhile, at Cr 20%, the shallow level was trapping Cr³⁺ ions near the valence band which converted n- to p-ReSe₂. The p-n ReSe₂ homojunction was constructed and electrically operated. Linear polarization light was illuminated on the homojunction resulted in higher energy conversion efficiency found in the E//b-axis polarization condition regarding its anisotropic behavior. These findings were hoped to contribute to advanced photovoltaic device application.

Keywords: 2D material TMDCs, anisotropic material, photovoltaic application, p-n homojunction, rhenium diselenide