Suppression of phase separation in InGaN layers grown on lattice-matched ZnO substrates

High-Resolution Electron Microscopy of Semiconductor Heterostructures and Nanostructures

“…Nevertheless, these examples of high homogeneity are still unusual in thin III-N epilayers and similar good qualities as those presented here have been rarely claimed, as, for example, in InAlN [138] or in InGaN [139], but for a very rough surface in the latter case. Some representative examples in the recent literature can be found for the state-of-the-art, but defective, ternary and quaternary III-Ns studied by some combination of HRTEM, HAADF, EDX, and EELS analyses.…”

The growth of III–V nitrides heterostructure on Si substrate by plasma-assisted molecular beam epitaxy

“…Recently, the enhancement of InGaN film quality has been reported by Kurouchi et al with the insertion of thin InN layer. In another study, the film quality of InGaN was found to be improved when ZnO was used as a substrate instead of sapphire [9][10][11][12].…”

Bottom‐Up Nano‐heteroepitaxy of Wafer‐Scale Semipolar GaN on (001) Si

“…The unique approach is realized by a self‐assembled ZnO‐nanorod buffer, eluding the costly and corrosive lithography/etching processes. ZnO shares the same crystalline symmetry and similar lattice constant (mismatch ≈ 1.9%) with GaN, imparting smooth atomic transition to the GaN/ZnO interface . Since the nanorods are synthesized via a templating procedure, being applicable to virtually any surface types, the growth of GaN and ZnO nanorods is performed on (001) Si, which is the substrate truly compatible with CMOS technology.…”

“…Since ZnO decomposes at the temperature above 600 °C and is particularly vulnerable in H + ambience, the growth of GaN is initiated from a low‐temperature nucleation layer to protect the nanorods as well as to facilitate lateral coalescence of the epilayer. Figure a,b respectively shows the nucleation layer of AlN and GaN grown at 580 °C for 45 min in N 2 ambience.…”

“…It is clear that the nucleation of AlN results in disordered crystal orientations, while the GaN nucleation layer preserves the well alignment of the nanorods and displays the surface of a pyramid‐like feature. One reason for the superior nucleation of GaN is the smaller lattice mismatch between GaN and ZnO, compared with that between AlN and ZnO . Further, it can be seen that the nanorods covered by AlN are noticeably thinner than those covered by GaN, making the AlN/ZnO structure more vulnerable in the subsequent high‐temperature growth.…”