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Domain epitaxy of crystalline BeO films on GaN and ZnO substrates

2018; Wiley; Volume: 102; Issue: 6 Linguagem: Inglês

10.1111/jace.16198

1551-2916

Seung Min Lee, Jung Hwan Yum, Eric S. Larsen, Shahab Shervin, Weijie Wang, Jae‐Hyun Ryou, Christopher W. Bielawski, Woo Chul Lee, Seong Keun Kim, Jungwoo Oh,

Ga2O3 and related materials

Abstract We demonstrated the growth of wurtzite‐crystalline beryllium oxide (BeO) thin films on GaN and ZnO substrates using atomic layer deposition (ALD). Single‐crystalline BeO were epitaxially grown on GaN. Despite the inherently large lattice mismatch of BeO and GaN atoms, the 6/5 and 7/6 domain‐matched structures dramatically reduced the residual strain in BeO thin films. On the other hand, the lattice mismatch of BeO and ZnO was not effectively accommodated in the mixed domains. X‐ray diffraction (XRD) confirmed the in‐plane crystallization of BeO‐on‐substrates in the (002){102} BeO ||(002){102} Sub orientation and relaxation degrees of 20.8% (GaN), 100% (ZnO). The theoretical critical thicknesses of BeO for strain relaxation were 2.2 μm (GaN) and 1.6 nm (ZnO), calculated using a total film energy model. Transmission electron microscopy (TEM) and Fourier‐filtered imaging supported the bonding configuration and crystallinity of wurtzite BeO thin films on GaN and ZnO substrates.