Electrical properties and transport mechanisms of p-znte/n-si heterojunctions
Department of Physics, Faculty of Education, Ain Shams University, Roxy, 9004 Cairo, Egypt
Corresponding author: Seyam80@yahoo.com
Accepted: 3 January 2008
Published online: 9 April 2008
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.
PACS: 73.40.Lq – Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions / 74.25.Fy – Transport properties / 72.20.-i – Conductivity phenomena in semiconductors and insulators
© EDP Sciences, 2008