Textured ZnO Thin Films on (0001) Sapphire Produced by Chemical Solution Deposition

Abstract

Highly textured zinc oxide films were produced on basal plane sapphire substrates by chemical solution deposition. Films with oriented growth were achieved by spin coating a 0.75 M precursor solution of zinc acetate dihydrate and ethanolamine in 2-methoxyethanol, heated at 300°C/10 min, then at 500°C/5 h, and finally at 850°C/12 h. Films were characterized with x-ray diffraction (XRD) and scanning and transmission electron microscopy. The films exhibited only the (0002) ZnO line in XRD diagrams, proving a very well-developed out-of-plane texture. At temperatures above 700°C the ZnAl 2 O 4 spinel was observed, which formed as a reaction layer between sapphire and ZnO. Few specimens produced both in-plane and out-of-plane oriented growth of ZnO on basal plane sapphire. It was hypothesized that the substrate miscut, uncontrolled for the current experiments, could be the cause of the infrequent growth of epitaxial films.

Hydrothermal growth of well-aligned ZnO nanorod arrays: Dependence of morphology and alignment ordering upon preparing conditions

“…5c), no diffraction peaks of wurtzite ZnO can be observed before annealing. However, after annealing, 002, 100 and 101 diffraction peaks of wurtzite ZnO can be clearly identified with 002 peak having the highest intensity, indicating that the annealing treatment results in the formation of oriented ZnO nanoparticles on ITO substrates [25]. These oriented particles help form wellaligned ZnO nanorods in the hydrothermal process, as can be seen in Figs.…”

Seeded epitaxial growth of ZnO thin films on MgAl2O4 substrates using the chemical solution deposition method

“…[12][13][14] There are several reports on the preparation of ZnO thin films using the chemical route both as polycrystalline phase [15][16][17] and as single crystalline phase. [18][19][20] Andeen 18 and on basal plane sapphire 19 using the chemical solution deposition (CSD) method, which are the only reports to date of epitaxial growth of ZnO thin films using chemical routes.…”

“…Attempts by Wessler et al to grow epitaxial ZnO films on MgAl 2 O 4 substrates were unsuccessful. 19 In the present study, we report on the growth of epitaxial ZnO thin films on MgAl 2 O 4 substrates by the CSD method. Epitaxial ZnO thin films, which could not be obtained directly on MgAl 2 O 4 substrates without preseeding with epitaxial islands, could be obtained by a two-step seeding process where epitaxial ZnO islands were grown on a substrate during the first step.…”

High Resolution X-Ray Diffraction Analyses of (La,Sr)MnO<sub>3</sub>/ZnO/Sapphire(0001) Double Heteroepitaxial Films

“…If we make an assumption that they are on the same β-positions with the spots of ZnO 1100 , then we can summarize the in-plane orientations of LSMO (111) [18] and Wessler, et al, [19] reported the epitaxial growth of this phase in the vicinity between ZnO epitaxial film on the c-sapphire substrate, with the epitaxial orientation of ( ) 0001 Sap . In our study, the same in-plane orientation with these reports was observed in the two samples of PL-HT and ML-HT grown at the higher temperatures.…”