Porous Nitride Light-Emitting Diodes

A porous InGaN/GaN blue light-emitting diode is demonstrated using selective area sublimation. Transmission electron microscopy reveals that the structure is porous down to the Si substrate; however, the porosity is higher in the GaN buffer, while smaller pores are observed in the active region. This change of porosity between the active region and the buffer is explained by the modification of the dislocation pattern in the heterostructure, which is evidenced by weak beam transmission electron microscopy on a nonporosified reference sample. Cathodoluminescence mapping and electron beam-induced current microscopy (EBIC) analyses are used to probe the impact of porosification on the optical and electrical properties of the structure at nanoscale dimensions. It is observed that neither the quantum well emission nor the p–n junction EBIC spatial profile was degraded after porosification with respect to the nonannealed reference sample. A light-emitting diode with a fully porous active region is fabricated using a parylene pore filling for electrical insulation, and its electroluminescence is analyzed.