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.