Large bandgap bowing of In_xGa_1–xN films and growth of blue/green In_xGa_1–xN/GaN MQWs on highly tensile strained GaN/Si(111) hetero structures

Abstract

. Gy, 68.55.Jk, 71.20.Br, 78.30.Fs, 78.55.Cr In x Ga 1-x N films and In x Ga 1-x N/GaN multiple quantum wells (MQWs) were grown on highly tensile strained GaN/Si(111) structure by MOCVD. Due to the large difference of lattice constant and thermal expansion coefficient between GaN and Si, GaN growth on Si(111) substrate usually leads to an initially high dislocation density and cracks. We demonstrate the low dislocation density and crack-free GaN films grown on Si(111) substrate introducing an AlN/GaN strain compensation layer and Si x N y dislocation masking layer. The Raman shift of E 2 phonon peak of GaN films on Si(111) substrate indicate the strong tensile stress (0.474 GPa). The In x Ga 1-x N bandgap energy depended on In-composition, which can be fitted by a larger bowing parameter of b = 4.5 eV in Ga-rich region (x < 0.25). Also, crack-free In x Ga 1-x N/GaN MQWs with blue and green emissions were demonstrated.

Stokes Shift and Band Gap Bowing in InxGa1-xN (0.060 ≤ x ≤ 0.105) Grown by Metalorganic Vapour Phase Epitaxy

“…The peak positions were thus determined by fitting two or three overlapping Gaussians to the luminescence peak. The peak positions of the higher energy component and lower energy components were shown in Table. The line widths of higher energy components accepted as band gap were also shown in Table. The band gap values obtained from the PL measurements were of the same order of magnitude as found in variety of InGaN systems [17][18][19][20]. However, our linewidth values are somewhat higher compared with reported values in literature.…”

Optical properties of InGaN/GaN MQW microdisk arrays on GaN/Si(111) template

“…MOCVD growth of GaN-based structures on Si(111) substrate constitutes mainly three parts, namely: a) Al preseeding process, b) AlN/GaN/AlN strain compensation structure, and c) Si x N y dislocation masking layer as reported our previous work [6]. At the time of growth of the GaN base structure, the substrate temperature and reactor pressure were kept constant at 1170 °C and 100 Torr, respectively, in H 2 environment.…”