THICKNESS AND TEMPERATURE-DEPENDENCE OF THE ELECTRICAL-RESISTIVITY OFAMORPHOUS SB2SE3 FILMS

Films of Sb2Se3 with different thicknesses deposited at a rate of 30 a ngstrom s-1 at room temperature were found to have amorphous structure . The dark electrical resistivity of Sb2Se3 films with silver electrod es increased with increasing thickness reaching a maximum value at 370 .8 nm after which it decreased with increasing thickness. For afl thic knesses resistivity decreased with increasing temperature. Up to 335 K , conduction was activated by 0. 15 eV characterizing an extrinsic con duction region. In the range 300-500 K, 0. 9 eV activated conduction f or samples with thickness greater than 400 nm and 1.17 eV activated co nduction in thicknesses less than 400 nm. Above 560 K a sudden drop in resistivity took place which was attributed to Mott transition. Charg e carrier concentration in the bulk material assumed the value 2.9 x 1 0(11) cm-3 on the basis of an empirical formula for the charge carrier concentration dependence on thickness. Decreasing negative TCR values were obtained with increasing temperature. The results were explained in view of the injecting and the blocking nature of the electrodes, c hange of stoichiometry of the film, heterogeneous and island film stru cture, variations in the number of trapping centres and conduction by either tunnelling or hopping mechanisms.