Blue (In,Ga)N Light-Emitting Diodes with Buried n+-p+ Tunnel Junctions by Plasma-Assisted Molecular Beam Epitaxy

TL;DR

This paper reports the growth and characterization of blue (In,Ga)N LEDs with a buried n+-p+ tunnel junction grown by plasma-assisted molecular beam epitaxy, demonstrating high-quality interfaces, good electrical properties, and potential for new device designs.

Contribution

It introduces a novel (In,Ga)N LED structure with a buried n+-p+ tunnel junction grown by plasma-assisted MBE, showing improved interface quality and electrical performance.

Findings

High-quality, sharp interfaces in (In,Ga)N MQWs verified by X-ray diffraction.

LEDs exhibit rectifying behavior with low junction resistivity.

Excellent current spreading due to low-resistance top n+-GaN layer.

Abstract

Blue light-emitting diodes (LEDs) consisting of a buried n+-p+ GaN tunnel junction, (In,Ga)N multiple quantum wells (MQWs) and a n+-GaN top layer are grown on single-crystal Ga-polar n+-GaN bulk wafers by plasma-assisted molecular beam epitaxy. The (In,Ga)N MQW active regions overgrown on the p+-GaN show chemically abrupt and sharp interfaces in a wide range of compositions and are seen to have high structural and optical properties as verified by X-ray diffraction and spatially resolved cathodoluminescence measurements. The processed LEDs reveal clear rectifying behavior with a low contact and buried tunnel junction resistivity. By virtue of the top n+-GaN layer with a low resistance, excellent current spreading in the LEDs is observed at low currents in this device structure. A few of new device possibilities based on this unique design are discussed.