In this letter, an enhancement-mode (E-mode) GaN p-channel field-effect transistor (p-FET) with a high current density of ?4.9 mA/mm based on a O₃-Al₂O₃/HfO₂ (5/15 nm) stacked gate dielectric was demonstrated on a p⁺⁺-GaN/p-GaN/AlN/AlGaN/AlN/GaN/Si heterostructure. Attributed to the p⁺⁺-GaN capping layer, a good linear ohmic I?V characteristic featuring a low-contact resistivity (ρ_c) of 1.34 × 10^?4 Ω·cm² was obtained. High gate leakage associated with the HfO₂ high-k gate dielectric was effectively blocked by the 5-nm O₃-Al₂O₃ insertion layer grown by atomic layer deposition, contributing to a high I_ON/I_OFF ratio of 6 × 10⁶ and a remarkably reduced subthreshold swing (SS) in the fabricated p-FETs. The proposed structure is compelling for energy-efficient GaN complementary logic (CL) circuits.

This work reports a demonstration of electrically injected GaN-based near-ultraviolet microdisk laser diodes with a lasing wavelength of 386.3?nm at room temperature. The crack-free laser structure was epitaxially grown on Si substrates using an Al-composed down-graded AlN/AlGaN multilayer buffer to mitigate the mismatches in the lattice constant and coefficient of thermal expansion, and processed into “sandwich-like” microdisk structures with a radius of 12?μm. Air-bridge electrodes were successfully fabricated to enable the device electrical characterization. The electrically pumped lasing of the as-fabricated microdisk laser diodes was evidenced by the rapid narrowing down of electroluminescence spectra and dramatic increase in the light output power, as the current exceeded the threshold of 248?mA.