Molecular beam epitaxy growth and pole figure analysis of ZnTe epilayer on m-plane sapphire

Abstract

ZnTe epilayers were grown on transparent ( ) oriented (m-plane) sapphire substrates by molecular beam epitaxy (MBE). The insertion of a low-temperature buffer layer was carried out, and the influence of the buffer layer annealing on crystallographic properties was investigated. Pole figure imaging was used to study the domain distribution in the layer. It was shown that strongest (211)- and (100)-oriented ZnTe epilayers were formed on m-sapphire when a ZnTe buffer layer annealed at 340 °C for 5-min was inserted. Also, it was confirmed that only (211) ZnTe epilayers were formed on the 2° tilted m-plane sapphire substrate. Thus, the single domain (211) ZnTe epilayer can be grown on the m-plane sapphire using MBE.

ZnTe layers on R ‐ and S ‐plane sapphire substrates

“…The atom arrangement on the sapphire's surface varies depending on the crystallographic orientation, and domain distributions of ZnTe layers grown on various sapphire substrate surfaces by molecular beam epitaxy (MBE) were reported in previous works [12][13][14][15][16][17][18]. Although there was a large lattice mismatch between ZnTe and sapphire, the improvement of the ZnTe epilayer quality by the insertion of thin buffer layers between the substrate and the epilayer was confirmed [12,13].…”

“…Although there was a large lattice mismatch between ZnTe and sapphire, the improvement of the ZnTe epilayer quality by the insertion of thin buffer layers between the substrate and the epilayer was confirmed [12,13]. A (111)-oriented ZnTe layer with single domain structure was formed on the c-plane sapphire substrate [12,14,18], while a (211)-oriented ZnTe layer was formed on the m-plane (10 10) substrate [13][14][15].…”

“…Hence, it was considered that the orientation of the ZnTe epilayer could be varied by using R-plane (10 14) and Splane (10 11) sapphire substrates. These studies were mainly carried out by using X-ray diffraction (XRD) pole figure imaging analysis, which was revealed to be a powerful method for ZnTe epilayers on sapphire substrates [12][13][14][15][16][17][18]. The interface between ZnTe and sapphire were also evaluated by using the transmission electron microscope and the lattice mismatch accommodation and related strain distribution were analyzed [14,17,18].…”

“…The growth of ZnTe layer was performed at 340 °C, and the growth rate and the film thickness were held constant at around 0.5 μm/hr and 1μm, respectively. The Zn to Te beam intensity ratio was also fixed at around unity [12][13][14][15][16][17][18].…”

“…XRD θ−2θ profiles and pole figures were collected using a Rigaku Smart-Lab system [12][13][14][15][16][17][18]. In this study, the in-plane configuration was used to measure the pole figure.…”