Numerical Simulation of Quantum Efficiency of Cd0.8Zn0.2S /CIGS Solar Cells

E Ihalane,E El Hamri,H Kirou,L Atourki,L Alahyane,K Bouabid,L Boulkaddat,A Ihlal

doi:10.6000/1929-6002.2014.03.04.6

E Ihalane, E El Hamri + Show 6 more

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https://doi.org/10.6000/1929-6002.2014.03.04.6

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Abstract

The paper presents a simulation study using the numerical simulator SCAPS-1D to model ZnO/Cd0.8Zn0.2S/CuIn(1-y)GaySe2/CuInSe2 structures. Effects of thickness of graded and ungraded CIGS absorbers and buffer layers on cell performance have been investigated with the aim to reach a higher efficiency. Quantum efficiency (QE) as function of wavelength and thickness of these layers was studied. The high efficiency of CIGS cells, in order of 22.05%, has reached with the absorbers thickness between 2μm and 3.5μm and with acceptor concentration of about 2.1016 cm3. Other hand, we investigate the effect of Cd0.8Zn0.2S ternary compound buffer on the top of the p-CIGS cell. These simulation results give some important indication to enable further development of multilayer thin-film solar cells based on CuInGaSe2 with Cd0.8Zn0.2S as buffer layer instead of CdS

Highlights

NUMERICAL SIMULATION METHODOLOGYA special quality of the Cu(In,Ga)Se2 (CIGS) semiconductor is its variable band gap, which can be changed by varying the Ga/(In+Ga) ratio
We have modeled the effect of varying the gap and the thickness of Cd(1-x)ZnxS buffer layer on the performance of CIGS solar cells
We reported the results of an analysis employing one dimensional simulation in order to optimize the performances of ZnO/ Cd0.8Zn0.2S/CIGS/CIS solar cell

Summary

NUMERICAL SIMULATION METHODOLOGY

A special quality of the Cu(In,Ga)Se2 (CIGS) semiconductor is its variable band gap, which can be changed by varying the Ga/(In+Ga) ratio. When alloying the CuInSe2 (CIS) with Ga to form CIGS thin films, the wider band-gap energy of the CIGS absorber layer can potentially better match the solar spectrum, and so increase the Voc parameter of cell with a little reduction of the short-circuit current density(Jsc) [1, 2]. CdS compound is serving as the buffer layer between CIGS and ZnO with band gap in order of 2.4 eV [3], which can be increased linearly by adding Zn to form Cd(1-x)ZnxS [4,5,6,7]. We have modeled the effect of varying the gap and the thickness of Cd(1-x)ZnxS buffer layer on the performance of CIGS solar cells

Numerical model

Effect of Buffer Layer

Effect of Band Gap Energy of CIGS

IQE Study as Function of Absorber Layer Thickness

CONCLUSION