Papers by Author: P.B. Barman

Abstract: Bulk samples of Se85-xTe15Bix (where x = 0, 1, 2, 3, 4, 5) glassy alloys are prepared by melt quenching technique. Thin films of the corresponding bulk samples are prepared by vacuum evaporation technique. I-V characteristics of Se85-xTe15Bix thin films are studied using Keithley 6487 picoammeter. Linear behavior of current has been observed at low voltage range and current is found to deviate from linearity i.e. tend towards non-Ohmic behavior in the higher voltage range. The value of resistance is also calculated in three different voltage ranges (0-90 V), (110-200 V) and (220-300 V) for the films under consideration. Maximum resistance has been observed for x = 1 and minimum resistance for x = 5. The conduction mechanism is discussed qualitatively and it is found to be of Poole Frenkel type for higher voltage range.

Abstract: The effect of bismuth (Bi) additions upon the physical properties, coordination number (m), constraints (Nc), density (ρ), molar volume (Vm), cohesive energy (CE), lone pair electrons (L) and glass transition temperature (Tg) of Ge20Te80-xBix (x = 0, 1.5, 2.5, 5.0) bulk glassy alloy has been investigated. The density and molar volume of the glassy alloys has been found to increase with increasing Bi content. The CE of the investigated samples has been calculated by using the chemical bond approach (CBA) and is correlated with a decrease in the optical band-gap with increasing Bi content. The glass transition temperature has been estimated by using the Tichy–Ticha approach and was found to increase with an increase in the Bi content.