Resistivity Reduction of Nanostructured Undoped Zinc Oxide thin Films for Ag/ZnO Bilayers Using APCVD and Sputtering Techniques

Abstract

Nanostructured undoped zinc oxide (ZnO) thin films were deposited using atmospheric pressure chemical vapor deposition (APCVD) on glass substrates using zinc acetate dehydrate [C 4 H 6 O 4 Zn·2H 2 O, ZnAc] in less than 2 minutes for each sample. In order to reduce the resistivity of ZnO films, a very thin layer of Ag was deposited on top of the films via the sputtering method to reduce resistivity from 2.89 to 0.31 Ω.cm, using only a 30Å silver coating. Structural, electrical and optical properties of the resulting bilayers were also investigated. The results show a polycrystalline structure in higher temperatures compared to rather amorphous ones in lower temperatures such as 325℃. The XRD patterns of the optimum polycrystalline films were identified as a hexagonal wurtzite structure of ZnO with the (002) preferred orientation. Also, sheet resistance decreased from 17.8 MΩ/⧠ to 28.9 KΩ/⧠ for the temperatures of 325℃ to 450℃, respectively. Based on the physical properties of undoped ZnO, substrate temperature is an important factor which affects the crystallite size and modifies electrical parameters. UV-vis measurements revealed a reduction in the transparency of the layers with increasing substrate temperature. A sharp cut-off was observed in ultraviolet regions at around 380 nm.

Effect of 4He2+ ion irradiation on the optical, electrical, morphological, and structural properties of ZnO thin films

“…On the other hand, the enhancement of resistivity in the range of 450 to 500 °C is due to the atomic composition of the semiconductor, that at 500 °C fits the perfect ZnO stoichiometry, as can be verified in figure 1. There are several reports [43][44][45] of temperature-dependent resistivity in ZnO thin films following the same resistivity evolution as ours. The comparison of the resistivity of the as-grown and irradiated ZnO thin films results is also exhibited in figure 8.…”

Study of Electrical Transport Properties of CZTS/MoSe2/glass Heterostructures

“…Figure 5A and 5B depicted that the slop of sample annealed at 450℃ is greater than the sample annealed at 500℃ which indicated the change from ohmic behavior to Schottky-type behavior of junction with rising temperature. The electrical conductivity increases exponentially with increasing temperature (Figure 4A and 4B), hence follows the typical trend for semiconductor thin films [30] . Below 250K, the reverse bias current in both samples is higher than the forward bias current.…”

Influence of Conditioning Temperature on Defects in the Double Al2O3/ZnO Layer Deposited by the ALD Method

“…Resistivity increases as post-treatment temperature is increased. The phenomenon was reported by other authors [ 27 , 28 ], but the fullest explanation can be found in the work of Wisz [ 29 ]. Columnar growth of the ZnO layer with temperature is accompanied by increase of the layer resistance.…”