Aluminum-Doped Zinc Oxide Thin Films Prepared by Sol-Gel and RF Magnetron Sputtering

Abstract

Zinc oxide (ZnO) thin films have become technologically important materials due to their wide range of electrical and optical properties. The characteristics can be further adjusted by adequate doping processes. In this paper, aluminum-doped zinc oxide thin films have been prepared on glass substrates using a sol-gel route and the radio-frequency magnetron sputtering process. The stoichiometry could be easily adjusted by controlling the nanosized precursor concentration and the thickness by dip-coating cycles. On the other hand, the mixed N 2 O/Ar plasma gas provided adequate N doping for the RF sputtering process. The results showed the low electrical resistivity of 21.5 Ω cm with the carrier concentration of −3.21 × 10 18 cm −3 for the n-type aluminium-doped zinc oxide film. They were 34.2 Ω cm and +9.68 × 10 16 cm −3 for the p-type aluminium-doped zinc oxide film. The optical transmittance has been as high as 85-90% in the 400-900 nm wavelength range. The aluminium-doped zinc oxide (2 at.% Al) films exhibited the hexagonal wurzite structure with (002) preferred crystal orientation. The electrical characteristics were depicted by the gradual increase in N and NO that occupy the oxygen vacancies.

Microwave plasma annealing of sol-gel deposited tantalum oxide and zinc oxide films

“…as stated in comparative studies on processing of TiO2 [11] and Al doped ZnO films [12]. Pristine solgel films require of activation processes, often performed through a thermal annealing that eliminates residual organics and promotes a film condensation.…”

Optimization of RF sputtering process parameters on electrical resistivity, deposition rate and sensitivity of Al-doped ZnO thin films grown on Si substrate using grey-Taguchi technique

“…The increase in electrical resistivity observed is due to the damage caused by the negative ions that collide with Al-doped ZnO thin films [40]. High power and extrinsic dopants [41] affect electrical nature. Therefore, the electrical resistance was found to be varied from 15.95 to 7.1 × 10 −3 -cm.…”

Growth of Aluminum Doped Zinc Oxide Nanostructure Thin Films by Nonconventional Sol‐Gel Method

“…[1][2][3][4][5][6][7][8] These features make ZnO thin films very attractive for different applications like transparent conductor oxide, gas sensors, piezoelectric sensors, semiconductor heterojunctions, solar cells, surface acoustic wave devices, light emitting diodes, nanolasers, and electrophotography. [4,[8][9][10][11][12][13] The undoped zinc oxide films having n-type conductivity, the transparency, band gap, and conductivity can be increased by adding dopants from to the II and III group such as Al, In,Ga, Cu, and Cd, [6,9,10,14,15] among these elements, Al is as of the most effective donor dopants because it is cheap, abundant, non-toxic material, and easy incorporation into the ZnO crystal structure. [9,16,17] Furthermore, the addition of aluminum ions to zinc sol solution can increase the number of nucleation sites.…”

“…[4,[8][9][10][11][12][13] The undoped zinc oxide films having n-type conductivity, the transparency, band gap, and conductivity can be increased by adding dopants from to the II and III group such as Al, In,Ga, Cu, and Cd, [6,9,10,14,15] among these elements, Al is as of the most effective donor dopants because it is cheap, abundant, non-toxic material, and easy incorporation into the ZnO crystal structure. [9,16,17] Furthermore, the addition of aluminum ions to zinc sol solution can increase the number of nucleation sites. [18] As a result, the aluminum doped ZnO thin films, it became attractive candidates in the optoelectronic industry.…”