Cu(InGa)Se₂ Thin-film Solar Cells with High Resistivity ZnO Buffer Layers Deposited by Atomic Layer Deposition

Abstract

The aim of our experiments is to improve the performance of Cd-free ZnO/Cu(InGa)Se 2 solar cells using a high-resistivity ZnO buffer layer. Buffer layers were deposited by atomic layer deposition (ALD) using diethylzinc (DEZn) and H 2 O as reactant gases. The structural and electrical properties of the ZnO films on glass substrates were characterized. A high resistivity of more than 10 3 ·cm and a transmittance of above 80% in the visible range were obtained. We focused on determining the optimum deposition parameters for the ALD-ZnO buffer layer. Results indicate that the thickness and resistivity of the ALD-ZnO buffer layer, as well as the heat treatment prior to the deposition of the buffer layer, affect the device characteristics. The best efficiency obtained with an ALD-ZnO buffer layer of solar cells without an antireflective coating was 12.1%. The reversible light soaking effect was observed in these devices.

Optical optimization of high resistance transparent layers in thin film cadmium telluride solar cells

“…The addition of a ZnO HRT buffer layer has been shown to be beneficial to CdS/CdTe solar cell efficiency [19]. ZnO has also been used as a HRT buffer layer in Cu(InGa)Se2 (CIGS) solar cell devices [20].…”

Atomic layer deposition: Prospects for solar cell manufacturing

“…[8]). ZnO based films [9,10,11,12,13,14] and In2S3 films [12,15,16,17,18,19] have been identified as most promis ing. A review of (ALD) buffer layers has been published by Harikos et al in 2005 [20].…”

High-efficiency Cu(InGa)Se2 solar cells with a zinc-based buffer layer

“…To complete the cell fabrication process, a ZnO window layer was grown by the metal-organic chemical vapor deposition (MOCVD) process [7]. The efficiency of solar cells with an as-grown CBD-ZnO was about 9%.…”

“…Furthermore, Nakada and Mizutani [5] reported a highly efficient CIGS solar cell by using a ZnS(O,OH) buffer layer. Up to now, our group also proposed several wide band gap Cd-free buffer layers, such as ZnInSe [6], ALD-ZnO [7], and In(OH) 3 :Zn 2+ [8].…”