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A high-performance, electrically driven, single-pyramid, micro light-emitting diode (micro-LED) was demonstrated. An insulated SiO2 layer, which served as a leakage current confinement layer (LCC layer), was deposited at the lower part of the pyramid, before the deposition of the transparent conducting layer. The micro-LED with the LCC layer demonstrated a decrease in reverse leakage current by two orders of magnitude and a 190% increase in light output at 500 µA compared to a micro-LED without an LCC layer. The small leakage current enables the micro-LED to operate with an ultra-low injection current (

In this study, crack-free InGaN/GaN multiple quantum well (MQW) LEDs with five-pair AlN/GaN distributed Bragg reflectors (DBRs) were grown on a Si(111) substrate using a linear compositionally graded AlGaN layer to compensate for tensile stresses. DBR-based LEDs exhibited higher light efficiency and better crystalline quality than non-DBR-based LEDs. Vertical-conducting DBR-based LEDs were realized using through-hole structure. Through-holes were formed from the n-GaN layer to the Si substrate and filled with metals, which connected the n-GaN layer and the Si substrate. Insulating AlN, high-resistivity AlGaN layers, and the large band offset at the AlN/Si interface were all shorted by the metal filled into the through-holes. Compared to DBR-based LED without through-holes, DBR-based LEDs with through-holes exhibited significantly better electrical and optical properties.

In this letter, a normally-off GaN recessed-gate MOSFET is demonstrated using a nonplasma gate recess technique, in which the access region with AlGaN/GaN heterostructure was selectively grown on a semi-insulating GaN/Si template to naturally form a recessed gate. The normally-off recessed-gate Al2O3/GaN MOSFET presents a high threshold voltage of 3.5 V and a maximum drain current density of 550 mA/mm (at a positive gate bias of 12 V). A maximum field-effect mobility of 170 cm2 V−1 s−1 and a large on/off current ratio of more than 107 was obtained, which indicates the high quality of the Al2O3/GaN interface.

An indium-surfactant-assisted delta doping method is reported to enhance the hole concentration and doping efficiency of Mg-doped p-type GaN grown by metal organic chemical vapor deposition. The hole concentration is increased to 1.5×1018 cm-3 by using this method, which is 92% higher than that of conventional delta doping. This higher carrier concentration leads to an improved doping efficiency of 12%. Secondary ion mass spectroscopy reveals that the Mg incorporation is increased by the In surfactant. Photoluminescence analysis suggests that the nitrogen vacancies may be suppressed by the induced indium. Temperature-dependent Hall measurements indicate that the Mg ionization energy and compensation ratio are reduced by the In surfactant.