Herein, self‐powered spectrally distinctive UV photodetectors (PDs) based on nanoporous epitaxial Ga2O3/GaN heterojunctions grown by metalorganic chemical vapor deposition (MOCVD) are reported. The nanoporous structures are formed by a novel self‐reactive etching (SRE) method, which significantly enhances the device performance. PDs with different porosities are fabricated and compared. In the self‐powered mode, the PD with the highest nanopore porosity exhibits the best performance, with an ultralow dark current of 0.04 nA, a fast photoresponse speed, and a high responsivity of 43.9 mA W−1 (35.8 mA W−1) under 254 nm (365 nm) illumination, which is 800% higher than that of the reference device without the porous structure. Furthermore, opposite current polarities are observed in the PDs under different illumination spectra, the mechanism of which is explained by the carrier transportation using the device band diagrams. This phenomenon can be used to distinguish different incident spectra, opening the door to more new applications. This work represents one of the first spectrally distinctive self‐powered UV PDs based on nanoporous Ga2O3/GaN heterojunctions and significantly benefits the development of multifunctional UV PDs.

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Vertical GaN trench-gate MOSFETs with ~130 nm stepped sidewalls in the p-GaN channel layer are studied and two significant influence have been observed. First effect is the degraded channel mobility which can be attributed to the increased probability of electron scattering under inversion conditions. Another influence is that only drain voltage (VDS) is applied over 30 V can the device turns on. It can be speculated that the stepped sidewall has a horizontal channel and no high enough transverse electric field to drive the electrons at low VDS.

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