Fabrication of the InGaN-Based Light-Emitting Diodes Through a Photoelectrochemical Process

InGaN-based light-emitting diodes (LEDs) with a lateral-etched (LE) undercut structure were fabricated through a photoelectrochemical-etching process. The LE-LED was fabricated with an undercut structure, where the InGaN layer acted as a sacrificial layer without reducing the effective emission area. The electroluminescence (EL) spectrum of the LE-LED had a wavelength blueshift phenomenon of 4.6 nm when compared with a standard-LED (ST-LED) at a 30-A/cm² current density. The wavelength blueshift phenomenon of the EL emission peaks were measured as 5.5 and 4.3 nm by varying the injection current density from 1.5 to 30 A/cm² for the ST-LED and the LE-LED. In a bias-dependent micro-photoluminescence measurement, the blueshift phenomenon of a peak wavelength for the LE-LED was smaller than for the ST-LED. These results were attributed to a partially reduced piezoelectric field in the InGaN active layer and larger light extraction efficiency in the LE-LED structure.