Growth and fabrication of semi-polar InGaN/GaN multi-quantum well light-emitting diodes on microstructured Si (001) substrates

Abstract

Semi-polar (1 − 101) InGaN/GaN light-emitting diodes were prepared on standard electronic-grade Si (100) substrates. Micro-stripes of GaN and InGaN/GaN quantum wells on semi-polar facets were grown on intersecting {111} planes of microscale V-grooved Si in metal–organic vapor phase epitaxy, covering over 50% of the wafer surface area. In-situ optical reflectivity and curvature measurements demonstrate that the effect of the thermal expansion coefficient mismatch was greatly reduced. A cross-sectional analysis reveals low threading dislocation density on the top of most surfaces. On such prepared (1 − 101) GaN, an InGaN/GaN LED was fabricated. Electroluminescence over 5 mA to 60 mA is found with a much lower blue-shift than that on the c-plane device. Such structures therefore could allow higher efficiency light emitters with a weak quantum confined Stark effect throughout the visible spectrum.

Полуполярные GaN-слои на наноструктурированной Si(100)-подложке

“…Синтез полуполярного GaN осуществляется как на подложках Si(11h) (где h = 2−7) [1,5], так и на разориентированных подложках Si(100) [6,7], а также с использованием буферных слоев 3C-SiC [8,9]. В работах [10][11][12] для синтеза полупо-…”

Monolithic semi-polar ( 1 1 ¯ 01 ) InGaN/GaN near white light-emitting diodes on micro-striped Si (100) substrate*

“…Over the last few years, GaN-based light-emitting diodes (LEDs) have been rapidly developed due to their low energy consumption and long lifetime. [1][2][3][4][5] By reducing the indium content, the band gap of InGaN increases from 0.7 eV to 3.4 eV, which corresponds to the wavelength of emission from ultraviolet to infrared. [6][7][8] Traditionally, polar blue InGaNbased LEDs are combined with phosphors to produce white LEDs [9][10][11][12] This method has achieved a high lumen efficiency (197.8 lm/W), [13] but this method is not a fully meaningful LEDs lighting technology, and there are still some shortcomings: the process is complex, [14] conversion efficiency is still far from the theoretical efficiency limit (298.7 lm/W), [13] and polar InGaN has a strong quantum confined stark effect (QCSE).…”