Abstract
Spray deposited kesterite (Cu2ZnSnS4) thin films were annealed in a controlled sulphur environment at 500 degrees C for one hour. Temperature dependence measurement of the electrical conductivity indicated two types of conduction are present: (i) at low temperatures due to nearest neighbor hooping (NNH) and (ii) at high temperatures due to hole excitation into the conduction. The as deposited films showed both the conduction mechanisms, but on annealing the CZTS film, the conduction takes place only due to hole excitation into the conduction band. The absence of NNH conduction is indicative of the effect of annealing in removing the defect levels which can be important for improving the device performance.