A Comprehensive Study on the Impact of Off-Stoichiometry and Mg Doping in CuCrO₂ Thin Films for Heterojunction Device Fabrication

In this work, we have demonstrated the growth of CuCrO2 thin films, a transparent conducting oxide (TCO), and evaluated their performance in optoelectronic applications. The films are grown using a simple solution-processed spin coating technique. Initially, the temperature dependence of material formation is studied to ensure the desired phase formation before experiments with Cu variations in CuCrO2. Electrical studies reveal that the Cu variation in the grown films impacts the hole concentrations and resistivity, with all films exhibiting p-type characters. The effect of Mg doping is also investigated, with the 2% Mg-doped CuCrO2 film exhibiting a maximum hole concentration of approximately 1019 cm–3. The essential parameters for the TCO are systematically investigated for Cu-poor, Cu-rich, and Mg-doped CuCrO2 thin films. The ultraviolet (UV) photodetection capability of the grown films is analyzed by fabricating a heterojunction with n-type ZnO nanorods. Devices with out-of-stoichiometry CuCrO2 films outperform those with stoichiometric films. The best results are obtained from the Mg-doped CuCrO2 device, showing a maximum photocurrent of 5.75 μA, with a responsivity of 70.9 mA/W and a detectivity of 2.44 × 1011 Jones under 372 nm.