Accepted Paper

P-type Behaviour of Doped ZnO Thin Films Prepared by Chemical Bath Deposition

V.J. Shukla1, R.P. Khatri2, A.J. Patel3
1L J Polytechnic, L J University, Ahmedabad, 382424 Gujarat, India
2Department of Physics, Gujarat Technological University, Ahmedabad, 382424, Gujarat, India
3Government Engineering College, Godhra, 389001 Gujarat, India
Abstract. Pure as well as Cu, Na and K doped ZnO thin films were deposited on glass substrate using aqueous solution of ZnCl2 and NH3 by chemical bath deposition method and have been studied for their thermoelectric behaviour. In conventional semiconductors, by changing the doping concentration from 0.1M to 0.5M of pure ZnO (n-type) and Na, K (Group IA), Cu (Group IB) doped ZnO (p-type) thin films will reduce the Seebeck coefficient (thermoelectric power) and resulted in a higher power factor. Transport coefficient was calculated using the graph of thermoelectric power vs inverse of temperature. The sign of measured thermoelectric power shows that pure ZnO is n-type but all doped ZnO are p-type. It is found that ZnO is a nondegenerate from the graph of Peltier coefficient vs temperature. The values of slope of the Jonker plot (Seebeck coefficient versus logarithm of conductivity) are around kB/e (86.15 μV/K) for pure ZnO, and 0.1M to 0.5M K doped ZnO thin films; and lower than kB/e for 0.1M to 0.5M Cu doped, 0.1M to 0.5M Na doped ZnO thin films.

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