Crystal quality improvement of a-plane GaN using epitaxial lateral overgrowth on nanorods

Titanium oxide nanoparticles spin-coated onto r-plane sapphire substrate: Effects on structural and optical properties of nonpolar a-plane GaN and InGaN/GaN multiple quantum wells

“…3(d)] samples, were (5.570.5) Â 10 9 cm À 2 and (3.670.6) Â 10 9 cm À 2 , respectively. This determined dislocation density of TiO 2 NP-related sample was close to (of the same order of magnitude) that in the case of GaN grown by LEO on a nanorod GaN template [17], by increasing the time of three-dimensional (3D) growth [18] to reduce defect densities. f¼01).…”

Investigation of emission polarization and strain in InGaN/GaN multiple quantum wells on nanorod epitaxially lateral overgrowth templates

“…Based on these experimental results, the variation of in-plane strain has been analyzed in our a-plane InGaN/GaN MQWs samples grown on the GaN templates with different nanorod height. The strain relaxation in the regrown layer including MQWs structure by using the nanorod template is believed to be one of the reasons for obtaining better crystal quality in terms of the narrow X-ray rocking curves [11]. Furthermore, the correlation between the average in-plane strain in the InGaN active layer and the polarization ratio is summarized, as shown in Fig.…”

“…1 (a) shows the sketch of the InGaN/GaN MQWs structure grown on a-plane GaN nanorod epitaxial lateral overgrowth templates. The detailed processes for a-plane GaN nanorod template have been described elsewhere [11]. The diameter of the nanorod is about 300−500 nm and the nanorod density is estimated to be around 6×10 8 /cm 2 according to the scanning electron microscope (SEM) image shown in Fig.…”

Optical Properties of A-Plane InGaN/GaN Multiple Quantum Wells Grown on Nanorod Lateral Overgrowth Templates

“…In our previous work [13], by utilizing AFM scanning, x-ray diffraction measurement, and TEM observation, we have demonstrated that the crystal quality of a-plane GaN NRELOG films can be gradually improved with the increase in the etching depth (t) of the nanorod templates. In order to observe the microstructure of the a-plane MQWs grown on NRELOG GaN template and as-grown GaN template, the typical bright-field cross-sectional TEM image near [1100] GaN zone axis is performed as shown in Fig.…”

“…Lateral epitaxial overgrowth (LEO) techniques were widely employed in the past to reduce defect density in nonpolar GaN [12]. In our previous work, we performed the LEO on a series of nanorod templates with varied etching depth to realize the defect-reduction and quality improvement in the subsequently grown a-plane GaN layer [13]. The average TD density can be reduced from 3×10 10 to 1×10 9 cm −2 .…”