Passivation of oxygen-related donors in microcrystalline silicon by low temperature deposition
- 10 April 2001
- journal article
- research article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 78 (16), 2330-2332
- https://doi.org/10.1063/1.1364657
Abstract
Low-temperature processing for high-performance solar cells based on hydrogenated microcrystalline silicon (μc-Si:H) has been developed using a conventional rf plasma-enhanced chemical vapor deposition (PECVD) technique at an excitation frequency of 13.56 MHz under a high deposition pressure condition. Among pin type solar cells, it is found that deposition temperature of i-layer at 140 °C is effective particularly for improving open circuit voltage (Voc), surprisingly without deteriorating short circuit current or fill factor. Carrier density of undoped μc-Si abruptly decreases for deposition temperatures lower than 180 °C, and the improvement of Voc is ascribed to a decrease of shunt leakage current arising from the oxygen-related donors. This implies that oxygen-related donors can be passivated at low deposition temperatures and that hydrogen plays an important role for the passivation. We propose a simple model for the hydrogen passivation of oxygen related donors. We apply this passivation technique to solar cells, and consequently a conversion efficiency of 8.9% (Voc=0.51 V, Jsc=25 FF=0.70) has been obtained in spite of an oxygen concentration of in combination with device optimization such as a p-layer. Effect of deposition temperature of i-layer upon other solar cell parameter, short circuit current, and fill factor is also discussed.
Keywords
This publication has 11 references indexed in Scilit:
- Hydrogenated microcrystalline silicon: how to correlate layer properties and solar cell performanceJournal of Non-Crystalline Solids, 2000
- Thin film Si solar cell fabricated at low temperatureJournal of Non-Crystalline Solids, 2000
- Intrinsic microcrystalline silicon: A new material for photovoltaicsSolar Energy Materials and Solar Cells, 2000
- Crystalline Si thin-film solar cells: a reviewApplied Physics A, 1999
- Microcrystalline silicon and micromorph tandem solar cellsApplied Physics A, 1999
- High Rate Deposition of Microcrystalline Silicon Using Conventional Plasma-Enhanced Chemical Vapor DepositionJapanese Journal of Applied Physics, 1998
- A Significant Reduction of Impurity Contents in Hydrogenated Microcrystalline Silicon Films for Increased Grain Size and Reduced Defect DensityJapanese Journal of Applied Physics, 1998
- Device grade microcrystalline silicon owing to reduced oxygen contaminationApplied Physics Letters, 1996
- Nature of Localized States in Hydrogenated Si–Based Amorphous Semiconductor Films Elucidated from LESR and CPMJapanese Journal of Applied Physics, 1989
- ANNEALING STUDIES ON LOW OPTICAL ABSORPTION OF GD a-Si:H USING PHOTOACOUSTIC SPECTROSCOPYLe Journal de Physique Colloques, 1981