Zinc telluride thin films have been deposited on glass and silicon wafers
substrates at room temperature by thermal evaporation technique in a vacuum
of 10−5 Torr. The thickness dependence of both the dc electrical
resistivity and thermoelectric power of ZnTe were carried out at room
temperature and after being annealed over a thickness range from 22 nm to
170 nm. The type of conduction, the carriers concentration and the
conduction mechanisms were revealed. The average thermal activation energy
ΔE equals to 0.324 eV for the as deposited films and 0.306 eV for
annealed films, it is found to correspond with the ionization energy
reported for intrinsic defect levels in ZnTe. Seebeck coefficient
measurements showed that ZnTe thin films behave as p-type semiconductor and
the average value of the free charge carrier concentration is found to be
1.6 × 1019 cm−3.
The built-in voltage, the widt of the depletion region, the diode quality
factor and the operating conduction mechanisms have been determined from
dark current-voltage (I − V) and capacitance-voltage
(C − V) characteristics of
p-ZnTe/ n-Si heterojunctions.