Nano Technology Enhanced Performance of a- (GeS2)100-xGax /Ge,n,p-Si Hereterojunction

Abstract

The (GeS2)100-xGax thin films have been prepared by thermal evaporation under vacuum of (10 -5 Toor) with thickness (  50nm) at different substrate like glass, single crystal Ge, Si n and p – type at room temperature. We devoted in this work on the effect of gallium concentration (0,6,12 , and 18%)on the optical properties of (GeS2)100-xGax thin films like (the optical energy gap (Eg ),the optical constants (the refractive index (n) ,the extinction coefficient (k) and the real (ε1 ) and the imaginary (ε2 ) part of dielectric constant. The optical energy gap values were found to decrease in regular manner with increase of Ga concentration of ternary compound in opposite with the optical constants which showed a systematic decrease with increase Ga concentration. The Energy Dispersive x-ray fluorescence (EDX) analysis revealed that thin films has a nearly stoichiometric composition. In this work, the effect of gallium concentration on performance of(GeS2)100-xGax /n-Si, (GeS2)100-xGax /p-Si and (GeS2)100-xGax /p-Ge heretojunctions had been investigated using nano layer. The optimized device has an efficiency of ~20% at room temperature. Investigations on the optimized device showed that gallium concentration has significant effect on the photovoltaic performance. The outcomes result indicates that the photocurrent of and short circuit voltage Voc of the prepared heterojunctions increase in the first and then decreases with increasing of gallium concentration.