Photovoltaic Photodetectors Based on In₂O₃/InN Core–Shell Nanorods

Indium nitride (InN)-based nanostructures have attracted substantial interest in the development of next-generation nanostructured optoelectronic devices. By expanding the light absorption range, the concept of heterostructures is of paramount significance in optoelectronics. Herein, we report a self-powered photodetector using In2O3/InN core–shell nanorods (NRs). InN NRs were grown using molecular beam epitaxy, and a radial In2O3/InN core–shell NR heterojunction with an In2O3 polycrystalline sheath layer was fabricated using hydrogen plasma treatment. The temperature-dependent current–voltage characteristics exhibit nonideal behavior, and the interface states cause deviation in barrier heights (BHs). The calculated BHs for InN and In2O3/InN core–shell heterostructure are estimated to be 0.47 and 0.62 eV, respectively. The In2O3/InN core–shell heterostructure achieved the highest photosensitivity and detectivity values of 3.22 A/W and 1.07 × 1011 Jones under λ = 465 nm (0.64 mW/cm2), respectively, in the self-power mode. This figure of merit is retained in 382–465 nm spectral regions. The maximum responsivity noticed at 465 nm is believed to be the intermediate oxygen defect energy levels within the forbidden gap of In2O3. The high performance was also attributed to the passivation of the InN NR surfaces by In2O3. The study would be beneficial for the development of solar-blind photodetectors.