thin filmsAbstract
Stoichiometric thin films of 
were prepared by the thermal evaporation technique; the as-deposited films were non-crystalline and the crystallinity was built in on annealing at 423 K. The crystal structure as determined by both x-ray and electron diffraction showed that tetragonal films of 
phase were obtained. Both dark electrical resistivity 
and thermoelectric power (Seebeck coefficient S) were measured for films before and after annealing. The films showed n-type conduction; the existence of two distinct activation energies 
and 
belongs to two types of level: a shallow level of 
before annealing and 
after annealing and deep levels of 
for as deposited films and 
for annealed film. The deep level was also detected by the space charge limited current technique and the trap density 
is found to be 
. The obtained results are explained on the basis of an energy diagram of 
- proposed by Garlick.
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