Light Emission by Nanoporous GaN Produced by a Top-Down, Nonlithographical Nanopatterning

Abstract

Temperature-dependent photoluminescence (PL) spectroscopy is carried out to probe radiative recombination and related light emission processes in two-dimensional periodic close-packed nanopore arrays in gallium nitride (np-GaN). The arrays were produced by nonlithographic nanopatterning of wurtzite GaN followed by a dry etching. The results of Raman spectroscopy point to a small relaxation of the compressive stress of ~0.24 GPa in nanoporous vs. bulk GaN. At ~300 K, the PL emission is induced by excitons and not free-carrier interband radiative recombinations. An evolution of the emission spectra with T is confirmed to be mainly a result of a decay of nonexcitonic PL emission and less of spectral shifts of the underlying PL bands. A switching of excitonic PL regime observed experimentally was analyzed within the exciton recombination-generation framework. The study provides new insights into the behaviors and physical mechanisms regulating light emission processes in np-GaN, critical to the development of nano-opto-electronic devices based on mesoscopic GaN.

Nanoscale Structural and Emission Properties within “Russian Doll”‐Type InGaN/AlGaN Quantum Wells

“…The dot marked as Position 1 (the yellow dot and spectrum) at the bottom of the stack corresponding to the pure GaN region and the peak near 372 nm is a characteristic CL peak for bulk GaN. [39,40] Figure 2d,e show the CL line-scan results along the yellow and red arrows directions indicated in Figure 2b, respectively. According to our CL measurement, it is found that the InGaN/AlGaN QWs mainly emit in the range of 510-538 nm (indicated by the green arrows in Figure 2c, corresponding to green light).…”