Tunable optical and electrical properties of p-type Cu2O thin films

Abstract

The presented study stresses that the deposition temperature is an important parameter to determine the quality and properties of deposited Cu2O thin films on copper (Cu) and fluorine-doped tin oxide (FTO) substrates. The optical and electrical properties of chemical bath deposited (CBD) cuprous oxide (Cu2O) thin films with a variety of deposition temperatures (50, 60, 70, and 80 °C) have been extensively investigated. The X-ray diffraction studies reveal the cubic polycrystalline structure of deposited thin films. The scanning electron microscopy (SEM) exhibits a homogeneous thin film constituting Cu2O crystals for 60 °C. Optical studies show the least energy bandgap of 1.90 eV at the optimized deposition temperature. The Cu deposited Cu2O thin film possesses very little resistivity and higher charge carrier concentration mainly due to the contribution from the conducting Cu substrate. The Cu2O films exhibit p-type conductivity in addition to comparable Hall mobility and improved charge carrier concentration by two orders of magnitude in the case of FTO substrate (~ 1017 cm−3). The I–V characteristics of fabricated Schottky junction with the prepared optimized thin film is presented. This study establishes 60 °C as the optimum temperature for Cu2O thin film deposition on different substrates.