Synthesis and Characterization of System In(O,OH)S/i-ZnO/n+-ZnO

William Vallejo,G Gordillo,Carlos Diaz-Uribe

doi:10.1155/2017/4052373

William Vallejo, G Gordillo + Show 1 more

Open Access

https://doi.org/10.1155/2017/4052373

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Abstract

In this work, we fabricated system In(O,OH)S/i-ZnO/n+-ZnO to be used as potential optical window in thin films solar cells. i-ZnO/n+-ZnO thin films were synthesized by reactive evaporation (RE) method and In(O,OH)S thin films were synthesized by chemical bath deposition (CBD) method; all thin films were deposited on soda lime glass substrates. Thin films were characterized through X-ray diffraction (XRD), atomic force microscopy (AFM), and spectral transmittance measurements. Structural results indicated that both thin films were polycrystalline; furthermore, morphological results indicated that both thin films coated uniformly soda lime glass substrate; besides, optical characterization indicated that system had more than 80% of visible radiation transmittance.

Highlights

Since their discovery, thin film solar cells have been considered a real option to compete with conventional silicon based solar cells; fewer amounts of chemical reagents and lower costs of manufacture than costs in silicon solar cells construction are main features of these devices
General chalcopyrite-based solar cell structure is shown in Figure 1; in typical structure layers are deposited in sequence, molybdenum back contact, p-type CIGS absorber layer, n-type buffer layer, transparent conductor oxide (TCO), and top contact grid [2]
Pairs of electron-hole are produced and light path and electron extraction from device rely on optical window; buffer layer decreases the mechanical tension stress between absorbent layer and TCO electrode; besides, TCO is required for electron extraction from solar cells [3]

Summary

Introduction

Thin film solar cells have been considered a real option to compete with conventional silicon based solar cells; fewer amounts of chemical reagents and lower costs of manufacture than costs in silicon solar cells construction are main features of these devices. Pairs of electron-hole are produced and light path and electron extraction from device rely on optical window (composed of buffer layer and TCO); buffer layer decreases the mechanical tension stress between absorbent layer and TCO electrode; besides, TCO is required for electron extraction from solar cells [3] These devices use a CdS thin film as buffer layer in their structure; this layer improves mechanical heterojunction between absorbent layer and TCO; CdS depicts environmental hazards during manufacture of the layers; besides, this material has a small forbidden energy band gap (Eg = 2.4 eV); this low-energy band gap reduces photocurrent at wavelengths near the ultraviolet region, and this incomplete absorption of the visible spectrum for CdS buffer layers is considered to be responsible for the drop in quantum efficiency of chalcopyrite-based solar cells [4,5,6]. Results showed that system In(O,OH)S/i-ZnO/n+ZnO could be used as optical window to thin films solar cells

Experimental

Results and Discussions

Conclusions