Optical and Electrical Effects of p-typeμc-SiOx:H in Thin-Film Silicon Solar Cells on Various Front Textures

Chao Zhang,Vladimir Smirnov,Matthias Meier,Bernhard Holländer,Andreas Lambertz,Tsvetelina Merdzhanova,Aad Gordijn

doi:10.1155/2014/176965

Chao Zhang, Vladimir Smirnov + Show 5 more

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https://doi.org/10.1155/2014/176965

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Abstract

p-type hydrogenated microcrystalline silicon oxide (µc-SiOx:H) was developed and implemented as a contact layer in hydrogenated amorphous silicon (a-Si:H) single junction solar cells. Higher transparency, sufficient electrical conductivity, low ohmic contact to sputtered ZnO:Al, and tunable refractive index make p-type µc-SiOx:H a promising alternative to the commonly used p-type hydrogenated microcrystalline silicon (µc-Si:H) contact layers. In this work, p-type µc-SiOx:H layers were fabricated with a conductivity of up to 10−2 S/cm and a Raman crystallinity of above 60%. Furthermore, we present p-type µc-SiOx:H films with a broad range of optical properties (2.1 eV < band gapE04<2.8 eV and 1.6 < refractive indexn<2.6). These properties can be tuned by adapting deposition parameters, for example, the CO2/SiH4deposition gas ratio. A conversion efficiency improvement of a-Si:H solar cells is achieved by applying p-type µc-SiOx:H contact layer compared to the standard p-type µc-Si:H contact layer. As another aspect, the influence of the front side texture on a-Si:H p-i-n solar cells with different p-type contact layers, µc-Si:H and µc-SiOx:H, is investigated. Furthermore, we discuss the correlation between the decrease ofVocand the cell surface area derived from AFM measurements.

Highlights

There has been a continuous interest in the development and application of hydrogenated microcrystalline silicon oxide
We focus on the development and application of ptype μc-SiOx:H in thin-film silicon solar cells, that is, a mixed phase material containing a μc-Si:H and an amorphous silicon oxide (a-SiOx:H) phase
We report on the development of p-type microcrystalline silicon oxide material, fabricated by plasma enhanced chemical vapor deposition (PECVD), as single layer and its application in amorphous silicon single junction solar cells

Summary

Introduction

There has been a continuous interest in the development and application of hydrogenated microcrystalline silicon oxide (μc-SiOx:H). Our stateof-the-art p-type layer stack, which is used in amorphous single junction or tandem solar cells fabricated on sputtered aluminum doped zinc oxides (ZnO:Al) front side TCO (transparent conductive oxide), included a p-type μc-Si:H contact layer. It provides a low resistive TCO/p contact, as discussed elsewhere [7,8,9], but causes an additional parasitic absorption; detailed examination is shown in reference [6, 10]. We report on the development of p-type microcrystalline silicon oxide material, fabricated by plasma enhanced chemical vapor deposition (PECVD), as single layer and its application in amorphous silicon single junction solar cells. Glass investigate the influence of the surface texture on the solar cell’s IV-characteristics, external quantum efficiency (EQE), and reflectance

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Type A

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