The Effect of Post Deposition Treatment on Properties of ALD Al-Doped ZnO Films

Abstract

In this paper, aluminum-doped zinc oxide (ZnO:Al or AZO) thin films are grown using atomic layer deposition (ALD) and the influence of postdeposition UV–ozone and thermal annealing treatments on the films’ properties are investigated. X-ray diffraction (XRD) revealed a polycrystalline wurtzite structure with a preferable (100) orientation. The crystal size increase after the thermal annealing is observed while UV–ozone exposure led to no significant change in crystallinity. The results of the X-ray photoelectron spectroscopy (XPS) analyses show that a higher amount of oxygen vacancies exists in the ZnO:Al after UV–ozone treatment, and that the ZnO:Al, after annealing, has a lower amount of oxygen vacancies. Important and practical applications of ZnO:Al (such as transparent conductive oxide layer) were found, and its electrical and optical properties demonstrate high tunability after postdeposition treatment, particularly after UV–Ozone exposure, offers a noninvasive and easy way to lower the sheet resistance values. At the same time, UV–Ozone treatment did not cause any significant changes to the polycrystalline structure, surface morphology, or optical properties of the AZO films.

Al3+-modified ZnO thin film sensor fabricated by the sputtering method: Characterization and a carbon monoxide gas detection study

“…An increase in the weight percentages of aluminum to 0.09 wt% leads to an increase in the surface roughness properties of the film, such as the root main square (RMS) by 57.4% compared to the RMS of the pure zinc oxide film surface. 39 In contrast, the Hall measurements of the pure and doped films revealed the type of charge carriers and the possibility of calculating their concentrations and Hall motilities. At the laboratory temperature, it was found that all the aluminum-doped ZnO films were the n-type, and this is due to the behavior of aluminum atoms as donor impurities in the polycrystalline ZnO films and because the aluminum atoms occupy the substitutional sites for zinc, as is the case in single crystals.…”

Versatile r.f. magnetron sputtering doping method to produce aluminum‐doped zinc oxide films

“…The O 1s spectrum can be deconvolved into two peaks: one related to ZnO bonds in a wurtzite-like arrangement, and another one related to oxygen defects in the ZnO matrix caused by oxygen vacancies and surface adsorbed oxygen. 26,27 The deconvolutions of the O 1s spectrum resulted in one peak located at 530.0 eV corresponding to O 2 ions in a ZnO wurtzite-like environment, and a second peak at 531.6 eV attributed to defects and adsorbed oxygen. 28,29 Comparing this result to those of XRD, we can conclude that the increase in the r.f.…”

AlZnO magnetron sputtered thin film for photovoltaic application

“…Aluminum zinc oxide (AZO) is a transparent conducting oxide (TCO) material owing to its nontoxicity as well as its tunable optoelectronic properties [1][2][3][4][5]. AZO thin films are widely used in photonic devices such as light-emitting diodes (LED's) [6], thin film solar cells [7,8], flat panel displays [9] as well as sensing devices [10,11].…”