Plasma Processes and Film Growth of Expanding Thermal Plasma Deposited Textured Zinc Oxide

Abstract

Summary: Plasma processes and film growth of textured zinc oxide deposited from oxygen and diethyl zinc utilizing expanding thermal argon plasma created by a cascaded arc is discussed. In all conditions explored, an excess of argon ions and low temperature electrons is available, which represent the chemistry taking place. The plasma induced decomposition mechanism involves charge exchange with argon ions, and consecutive dissociative recombination with electrons emanating from the cascaded arc plasma source. The presence of reactive atomic species, specifically Zn* and O*, is confirmed with the help of optical emission spectroscopic measurements. The absence of residual carbon in the films suggests a mechanism involving the dissociation of the ZnC bonds in the plasma instead of at the surface. Film growth appears to proceed by the adsorption of particular zinc species, followed by subsequent reaction with oxygen, with the deposition rate being directly proportional to the arrival rate of the particular reactive species. It is suggested that atomic zinc adsorbs on the surface in a weakly bounded highly mobile state. Best intrinsic transparent conducting oxide quality, that is film conductivity, is obtained at the highest deposition rate.

Factors that Contribute to the Growth of Ag@TiO2 Nanofibers by Plasma Deposition

“…Very recently Ostrikov,24 when discussing the potentialities of plasma deposition as a tool for the preparation of nanostructured layers, stressed the importance of the plasma sheath formed at the surface of the substrate as a directional vector that favours the preferential development of such nanostructures. Texturing of oxide thin films prepared by plasma deposition is a known phenomenon widely studied in the literature 25. This seems particularly evident during the formation of supported carbon nanotubes by plasma deposition, although in this case the role of a metal catalyst is also essential 10–12.…”

Evolution of the electrical and structural properties during the growth of Al doped ZnO films by remote plasma-enhanced metalorganic chemical vapor deposition

“…The oxygen-poor environment promotes the increase in ZnO film conductivity because in this condition film substoichiometry ͑O/ZnϽ 1͒ is achieved, as also earlier reported for undoped ZnO films. 28 The sheet resistance gradient with film thickness was again investigated for these optimized conditions; the results, shown in Fig. 7͑b͒, indicate that the sheet resistance gradient is partially recovered, which suggests that the plasma chemistry alone can influence the film growth, in particular the initial growth.…”

The influences of O/Zn ratio and growth temperature on carbon impurity incorporation in ZnO grown by metal-organic chemical vapor deposition

“…2(a) shows the decomposition ratio of DEZn (1À I(T)/I(RT)) versus the growth temperature without oxygen source input. It is found that the decomposition starts to increase very fast at 673 K and reaches a high value at about 773 K, which is about 100 K higher than other reported values [12]. The reason for this difference may be that the actual substrate temperature is lower than the thermocouple indicated, as the thermocouple is not directly in contact with the rotating susceptor.…”

“…It was reported that thermal decomposition starts at the temperature of approximately 573 K [12], involving a homolytic dissociation of the Zn-C bond leading to the production of ethane, ethene and butane. When N 2 O is employed for ZnO growth, almost no direct reactions occur between N 2 O and DEZn: the low decomposition rate of DEZn and surface kinetics may dominate ZnO growth at most growth temperatures.…”