Effect of Al-doped on physical properties of ZnO Thin films grown by spray pyrolysis on SnO₂: F/glass

Abstract

Abstract. Transparent conducting thin films of aluminum-doped zinc oxide (ZnO:Al) have been deposited on SnO 2 :F/glass by the chemical spray technique, starting from zinc acetate (CH 3 CO 2 ) 2 Zn.2H 2 O and aluminum chloride AlCl 3 . The effect of changing the aluminum-to-zinc ratio y from 0 to 3 at.%, has been thoroughly investigated. It was found that the optical and electrical properties of Al doped ZnO films improved with the addition of aluminum in the spray solution until y=2%. At this Al doping percentage, the thin layers have a resistivity equal to 4.1 x 10 -4 Ω.cm and a transmittance of about 90 % in the region [600-1000] nm. XRD patterns confirm that the films have polycristalline nature and a wurtzite (hexagonal) structure which characterized with (100), (002) and (101) principal orientations. The undoped films have (002) as the preferred orientation but Al doped ones have (101) as the preferred orientation. Beyond y= 1%, peak intensities decrease considerably.

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

“…With increasing the aluminum concentration, the grain size decreased, which is similar to other results, [ 7,15,16,32–37 ] the energy band gap increased, which has been found by other methods. [ 7,11,12,13,15–17,19,28,30,32–34,38–44,45–51 ] The conductivity and carrier concentration increased with increasing the aluminum, which is similar to other reported results by other methods. [ 8,13,19,21,23,29,31,32,35,36,39–42,44,47–51,52–58 ]…”

“…[7,11,12,13,[15][16][17]19,28,30,[32][33][34][38][39][40][41][42][43][44][45][46][47][48][49][50][51] The conductivity and carrier concentration increased with increasing the aluminum, which is similar to other reported results by other methods. [8,13,19,21,23,29,31,32,35,36,[39][40][41][42]44,[47][48][49][50][51][52][53][54][55][56]…”

“…This result is similar to other reported results with AZO thin films grown by other methods. [ 8,13,19,21,23,29,31,32,35,36,39–42,44,47–51,52–58 ]…”

“…The increase in the energy band gap due to Moss-Burstein effect, after doping the free carrier concentration increased and the Fermi level shifted to a higher energy state into the conduction band, leading to optical band gap widening as it has been found in the AZO thin films grown by other methods. [7,11,12,13,[15][16][17]19,28,30,[32][33][34][38][39][40][41][42][43][44][45][46][47][48][49][50][51]…”

“…This result is similar to other reported results with AZO thin films grown by other methods. [8,13,19,21,23,29,31,32,35,36,[39][40][41][42]44,[47][48][49][50][51][52][53][54][55][56][57][58] The Hall measurement results are listed in Table 4; from this table, it can be found that the higher value of conductivity and carrier concentration were achieved at 3 wt% doping concentrations as shown in Figure 8…”