Synthesis and Characterization of a p-Type Boron Arsenide Photoelectrode

A p-type boron arsenide photoelectrode was prepared from a material consisting of a thin layer of boron arsenide on a boron substrate. The structure of the material was identified using X-ray diffraction and scanning electron microscopy, and the surface composition was determined by means of X-ray photoelectron spectroscopy. The electrode was found to be photoactive under both visible light and UV–vis irradiation and displayed a photocurrent of ∼0.1 mA/cm2 under UV–vis irradiation at an applied potential of −0.25 V vs Ag/AgCl. Mott–Schottky plots for this boron arsenide electrode displayed an estimated flat-band potential near the onset photopotential. The estimated indirect band gap, as determined from incident photon-to-electron conversion efficiency plots, is 1.46 ± 0.02 eV.