【Device Papers】Zero-bias photo-induced charge separation using built-in electric field at p-NiO/n-Ga₂O₃ heterojunction interface

      Researchers from the University of Central Florida have published a dissertation titled "Zero-bias photo-induced charge separation using built-in electric field at p-NiO/n-Ga₂O₃ heterojunction interface" in Journal of Applied Physics.

Abstract

      As a viable alternative to the challenging fabrication of robust β-Ga₂O₃ p–n homojunctions, this study investigates the variable-temperature photocurrent of p-NiO/n-Ga₂O₃ heterojunction photodiodes under zero-bias conditions. The device's built-in electric field is utilized to achieve efficient separation of non-equilibrium photogenerated carriers. To support the experimental findings, computer simulations of the electric field distribution at the heterointerface were performed and correlated with experimental current–voltage and capacitance–voltage measurements. The photocurrent measurements confirm the narrowing of the n-Ga₂O₃ bandgap with increasing temperature, consistent with predictions from the Varshni equation. The observed decrease in photocurrent amplitude at lower temperatures is attributed to bandgap widening, which results in a smaller number of non-equilibrium carriers generated by the excitation wavelength.

DOI：

https://doi.org/10.1063/5.0297247