The effects of deposition rate on the structural and electrical properties of ZnO:Al films deposited on (112̄0) oriented sapphire substrates

Abstract

Articles you may be interested inThe cooling effect on structural, electrical, and optical properties of epitaxial a-plane ZnO:Al on r-plane sapphire grown by pulsed laser deposition Appl. Phys. Lett. 101, 151907 (2012); 10.1063/1.4759032 Effect of substrate temperature on the properties of transparent conductive ZnO:Al thin films prepared by RF sputtering J. Vac. Sci. Technol. A 29, 051506 (2011); 10.1116/1.3610175 Structural, optical, and photocatalytic properties of ZnO:Al nanowall structure deposited on glass substrate by spray pyrolysis J. Vac. Sci. Technol. A 27, 885 (2009); 10.1116/1.3093878Comprehensive investigation of structural, electrical, and optical properties for ZnO:Al films deposited at different substrate temperature and oxygen ambient Aluminum doped zinc oxide (2nO:A.l) films were deposited on ( 1170) oriented sapphire substrates heated to 200 "C with a radio-frequency (rf) power ranging from 25 to 170 W for a deposition rate in the range 0.7-27.4 nm min -* by rf-magnetron sputtering from a ZnO target mixed with A&O3 of 2 wt. %. All of the films deposited were (0001) oriented singlecrystalline films with an internal stress. The stress was increased and degraded the crystallinity of the epitaxial film as a deposition rate was increased, and thus the Hall mobility and the resistivity of the film were, respectively, decreased and increased. However, the resistivities obtained were in the range about 1.4-3.0X 10 -4 Q cm, the values comparable to those for indium tin oxide film presently used as a transparent electrode. 3613

Low temperature growth of highly transparent c-axis oriented ZnO thin films by pulsed laser deposition

“…The value of 20 measured for the grown films was always less than that for bulk material (i.e. 34.47") more so for the Nd:YAG grown layers, implying that an in-built compressive stress developed during growth [2,3,141. Nevertheless, the values for the films grown by the excimer laser were very close to the tabulated value [ 11, corresponding to low stress for films grown at substrate temperatures below 35O'C and almost no stress at all for higher substrate temperatures.…”

“…Since such c-axis oriented films have been also obtained by using other deposition techniques when the substrate was glass or Si covered by its native oxide [2,[14][15][16][17][18][19]22,231, the reason for this preferred orientation is most likely chemical rather than crystallographic in nature. The central concept of this argument is that the Zn atoms as opposed to the 0 atoms of the ZnO are attracted preferentially and bonded to the oxygen species already present on the substrate surface.…”

Improved electrical transport in Al-doped zinc oxide by thermal treatment

“…These high values were mostly achieved by a very high carrier concentration, exceeding 10 21 cm −3 , while maximum mobilities were around 50 cm 2 / Vs. For sputtered films similar properties were achieved by Igasaki on sapphire substrates. 37,38 Nevertheless the emphasis in TCO research for photovoltaics is on high mobilities. As deposited films, usually prepared by various magnetron sputtering processes, on glass usually have mobilities up to around 40 cm 2 / Vs at carrier concentrations between 2 and 8 ϫ 10 20 cm −3 ͓see for instance ͑Ref.…”

Compensation in Al-Doped ZnO by Al-Related Acceptor Complexes: Synchrotron X-Ray Absorption Spectroscopy and Theory

“…There are several deposition techniques that have been reported to successfully produce AZO thin films. These include chemical vapor deposition [10], magnetron sputtering [11], spray pyrolysis [12], and pulsed laser deposition [13].…”