Effects of GaN template on atomic‐layer‐epitaxy growth of ZnO

Abstract

ZnO layer was epitaxially grown on GaN template by atomic layer epitaxy (ALE) using Diethylzinc (DEZ) and H 2 O at the growth temperature of 250 ℃. By reflection high-energy electron diffraction (RHEED) measurements, spotty pattern was observed for the ZnO layer directly grown on c-plane sapphire substrate, while streaky pattern was observed for that grown on GaN template. Full-width at halfmaximum (FWHM) value of (0002) X-ray rocking curve of ZnO layer was greatly reduced from 4.96° to 0.103° by using GaN template. By photoluminescence (PL) measurements, only the near bandedge emissions were observed. FWHM of the neutral-donor-bound-exciton (D 0 X) emission line was reduced from 18.7 to 16.1 meV by using GaN template.

Atomic layer deposition of epitaxial ZnO on GaN and YSZ

“…1(b) is a X-ray rocking curve of ZnO (0 0 0 2) reflection with the full-width at half-maximum (FWHM) value of 324 arcsec. This FWHM value is slightly better than other reported data for ZnO epi-layers grown on GaN substrate by ALD [3], indicating that the film is of good structural quality. In contrast, when we directly deposited on sapphire in similar experimental conditions, it was found no epitaxy of ZnO.…”

“…Other advantages of ALD include uniformity with large areas, good reproducibility, multilayer processing capability, and high-quality films at relatively lower temperature [2]. Although ZnO deposition by ALD has been developed in early beginning of ALD in 1980s, epitaxial growth of ZnO has received relatively less attention [3,4].…”

“…Thus, optimization of ALD conditions for ZnO epitaxial growth can be experimentally found without much difficulty [3,6]. Also, yttria-stabilized zirconia YSZ (1 1 1) single-crystal substrate which has a lattice mismatch of about 10% with ZnO [7], is used for comparison with GaN substrate.…”

Flow modulation epitaxy of ZnO films on sapphire substrates

“…Many deposition techniques have been used to grow ZnO films [5][6][7], including molecular beam epitaxy (MBE), pulsed laser deposition (PLD), organometallic vapor phase epitaxy (OMVPE), DC or RF magnetron sputtering and atomic layer deposition (ALD). One of the challenges for OMVPE of ZnO is the high degree of reactivity between the gas phase precursors, typically diethylzinc (DEZn), and the oxygen precursors such as O 2 , H 2 O etc.…”

The Structure and Ultraviolet Electroluminescence of n-ZnO-SiO2-ZnO Nanocomposite/p-GaN Heterojunction LED

“…The most distinctive feature of ALD is that each precursor is alternatively introduced into the chamber and the chemical reactions proceed solely at the substrate surface, leading to self-limiting and layer-bylayer growth. Although ZnO deposition by ALD has been developed in 1980s, epitaxial growth of ZnO has received relatively less attention (3)(4).…”