Vertically conducting deep-ultraviolet light-emitting diodes with interband tunneling junction grown on 6H-SiC substrate

Abstract

Vertically conducting deep-ultraviolet (DUV) light-emitting diodes (LEDs) with a polarization-induced backward-tunneling junction (PIBTJ) were grown by metal–organic chemical vapor deposition (MOCVD) on 6H-SiC substrates. A self-consistent solution of Poisson–Schrödinger equations combined with polarization-induced theory was applied to simulate the PIBTJ structure, energy band diagrams, and free-carrier concentration distribution. AlN and graded AlxGa1−xN interlayers were introduced between the PIBTJ and multiple quantum well layers to avoid cracking of the n-Al0.5Ga0.5N top layer. At a driving current of 20 mA, an intense DUV emission at ∼288 nm and a weak shoulder at ∼386 nm were observed from the AlGaN top layer side. This demonstrates that the PIBTJ can be used to fabricate vertically conducting DUV LED on SiC substrates.