Synthesis of InGaN nanowires via metal-assisted photochemical electroless etching for solar cell application

This article reports on the studies of InGaN Nanowires (InGaN NWs) prepared via metal- assisted photochemical electroless etching method with Pt as catalyser. It has been found that etching time greatly influences the growth of InGaN NWs. The density and the length of nanowires are increased for longer etching time and excellent substrate coverage was observed. The synthesis mechanism of InGaN NWs using metal assisted photochemical electroless etching method and the energy band diagram were presented. Photoluminescence (PL) measurements of InGaN NWs shows a red-shift PL peaks compared to the as grown associated to the relaxation of compressive stress. Furthermore, Raman measurements shows a large shift of 20 cm⁻² of the A₁(LO) modes, which is strongly related to the In composition. The Raman results confirm the reduction of the In composition in the epilayer due to the etching process and formation of nanowires. Therefore, the observed large shift to the lower frequency in Raman spectra confirms the stress relaxation. This new and low-cost etching method to synthesize strain relaxed InGaN NWs will be suitable for III-nitride solar cell applications.