Electrical and optical properties of Al-doped ZnO and ZnAl2O4 films prepared by atomic layer deposition
Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics, Nankai University, Weijin Road 94, Tianjin, 300071, China
Nanoscale Research Letters 2013, 8:144 doi:10.1186/1556-276X-8-144Published: 28 March 2013
ZnO/Al2O3 multilayers were prepared by alternating atomic layer deposition (ALD) at 150°C using diethylzinc, trimethylaluminum, and water. The growth process, crystallinity, and electrical and optical properties of the multilayers were studied with a variety of the cycle ratios of ZnO and Al2O3 sublayers. Transparent conductive Al-doped ZnO films were prepared with the minimum resistivity of 2.4 × 10−3 Ω·cm at a low Al doping concentration of 2.26%. Photoluminescence spectroscopy in conjunction with X-ray diffraction analysis revealed that the thickness of ZnO sublayers plays an important role on the priority for selective crystallization of ZnAl2O4 and ZnO phases during high-temperature annealing ZnO/Al2O3 multilayers. It was found that pure ZnAl2O4 film was synthesized by annealing the specific composite film containing alternative monocycle of ZnO and Al2O3 sublayers, which could only be deposited precisely by utilizing ALD technology.