Planar GaN-Based Blue Light-Emitting Diodes with Surface p-n Junction Formed by Selective-Area Si-Ion Implantation

A GaN-based blue light-emitting diode structure, featuring a surface GaN p-n junction formed by selective-area Si implantation on a p-GaN surface layer, serving as a carrier injector, is demonstrated. Blue InGaN/GaN multiple quantum wells (MQWs) located under the Si-implanted planar GaN p-n junction emit a single-peak spectrum without defect-related yellow luminescence (YL). The absence of YL-band is attributed to the fact that the Si-implanted GaN homojunction only behaves a carrier injector rather than a photon injector. In other words, the single-peak blue emission does not originate from optical pumping that UV light emitted from the surface GaN homojunction (i.e., the GaN band-edge emission) to pump the underlying blue InGaN/GaN MQWs. The analysis of current-voltage characteristics and dynamic resistance tentatively elucidate that the planar surface p-n junction induces extra current paths to facilitate the carrier injection at high current injection.