Optical and electronic properties of delafossite CuBO₂ <i>p</i>-type transparent conducting oxide

Abstract

CuBO2 delafossite was prepared by solid state reaction and calcined/sintered at 1005 °C. The optical properties of this p-type transparent conducting oxide were investigated. Its crystal structure, morphology, composition, oxygen decomposition, and optical and electronic properties were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, thermal gravimetric analysis (TGA), ultraviolet-visible-near-infrared (UV-VIS-NIR) and fluorescence spectroscopies, Seebeck coefficient, and electrical conductivity measurements. CuBO2 delafossite possesses a hexagonal space group R3¯m. TGA indicated a weight loss of 10%, which was attributed to excess oxygen. The positive Seebeck coefficient confirmed p-type behavior. Emission at 355 nm indicated a direct band type transition, and the UV-VIS-NIR spectrum indicated an optical direct gap of 3.6 eV. Activation energies for carrier production and electrical conduction were 0.147 and 0.58 eV, respectively, indicating the thermal activation of carriers. CuBO2 delafossite is a p-type transparent conducting oxide with a wide band gap and may have potential in industrial p-type electrodes.