Studying the effect of copper on the p-ZnTe/n-AgCuInSe2/p-Si for thin films solar cell applications

Abstract

A thin film of AgInSe2 and Ag1-xCuxInSe2 as well as n-Ag1-xCuxInSe2 /p-Si heterojunction with different Cu ratios (0, 0.1, 0.2) has been successfully fabricated by thermal evaporation method as absorbent layer with thickness about 700 nm and ZnTe as window layer with thickness about 100 nm. We made a multi-layer of p-ZnTe/n-AgCuInSe2/p-Si structures, In the present work, the conversion efficiency (η) increased when added the Cu and when used p-ZnTe as a window layer (WL) the bandgap energy of the direct transition decreases from 1.75 eV (Cu=0.0) to 1.48 eV (Cu=0.2 nm) and the bandgap energy for ZnTe=2.35 eV. The measurements of the electrical properties for prepared films showed that the D.C electrical conductivity (σd.c) increased with increasing Cu content for AgCuInSe2 thin films. So the electrical conductivity changed from 1 (Ω.cm)-1 to 29.96 (Ω.cm)-1 when x changed from 0.0 to 0.2. The prepared thin films have two activation energies (Ea1 & Ea2) in the temperature ranges of (300-393) K and (303-473) K. The C-V measurements revealed that all prepared heterojunctions were of the abrupt type and the junction capacitance reduced while the width of depletion region and the built-in potential increased with increasing the Cooper content. The current-voltage characteristics under dark condition of AgCuInSe2 heterojunctions, the current-voltage measurements under illumination showed that the performance of heterojunction solar cell improved with increasing Cu content. The result indicated that the prepared solar cell with 0.2 Ag content exhibited the highest efficiency (η = 1.68%) compared to other prepared solar cells.

Fabrication and investigation of zinc telluride thin films

“…Tauc equation and lambert law have been used to calculated the absorption coefficient α and the energy gap (Egopt) respectively from absorption spectrum [30]. Optical Constant such as n: refractive index, k : extinction coefficient, real part ε r & imaginary part ε i of dielectric constant can be measured, dielectric loss and optical conductivity [30,31,32]. The carrier type, concentrations and their mobility were measured by Hall effect studies using the Van der Pauw -Ecopia HMS -3000.…”

Effect of Sulfur on Characterization of AgInSe1.8S0.2 Thin Film and n-AgInSe1.8S0.2 / p-Si Solar Cell

“…This causes a shift of the Fermi level towards the conduction band, leading to an increase in the carrier concentration [20,21]. The effects of Copper on Ag0.8Cu0.2InSe2 Fabrication and study the influence of vacuum annealing (473,573) K on structure and optical properties [10] The efficiency 3.07% of silver indium selenide with Zinc-diffused [22] the highest efficiency (η = 1.68%) of p-ZnTe/n-AgCuInSe2/p-Si [23] In this study the role of Sulfur S with ratio 0.2 in AIS occupies the anion (Se) and the relatively electronegativity of S (2.58) compared with Ag (1.93), In (1.78), Se (2.55), the selenide and Sulfur are part of the elements of the third period and group VI from Periodic Table [24]. The goal of this research is to investigate the influence of sulfur (S) on the optical, structural properties, and Hall Effect of AgInSe2 (AIS) thin films.…”