CdS/CdTe Heterostructures for Applications in Ultra-Thin Solar Cells

Materials - Tập 11 Số 10 - Trang 1788
K. Gutiérrez Z-B1, P. G. Zayas-Bazán1, O. de Melo2,3, F. de Moure‐Flores4, J.A. Andraca-Adame5, Luis A. Moreno‐Ruiz5, Hugo Martínez‐Gutiérrez5, S. Gallardo‐Hernández6, J. Sastré‐Hernández1, G. Contreras‐Puente1
1Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Ciudad de México C.P. 07738, Mexico
2Departamento de Materiales de Baja Dimensionalidad, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Ciudad de México C.P. 04510, Mexico
3Facultad de Física, Universidad de La Habana, Colina Universitaria, La Habana C.P. 10400, Cuba
4Facultad de Química, Materiales-Energía, Universidad Autónoma de Querétaro, Querétaro C.P. 76010, Mexico
5Centro de Nanociencias y Micro y Nanotecnologías del IPN, Ciudad de México C.P. 07738, Mexico
6Departamento Física, Cinvestav-IPN, Ciudad de México C.P. 07360, Mexico

Tóm tắt

The preparation of ultra-thin semi-transparent solar cells with potential applications in windows or transparent roofs entails several challenges due to the very small thickness of the layers involved. In particular, problems related to undesired inter-diffusion or inhomogeneities originated by incomplete coverage of the growing surfaces must be prevented. In this paper, undoped SnO2, CdS, and CdTe thin films with thickness suitable for use in ultra-thin solar cells were deposited with a radiofrequency (RF) magnetron sputtering technique onto conductive glass. Preparation conditions were found for depositing the individual layers with good surface coverage, absence of pin holes and with a relatively small growth rate adapted for the control of very small thickness. After a careful growth calibration procedure, heterostructured solar cells devices were fabricated. The influence of an additional undoped SnO2 buffer layer deposited between the conductive glass and the CdS window was studied. The incorporation of this layer led to an enhancement of both short circuit current and open circuit voltage (by 19 and 32%, respectively) without appreciable changes of other parameters. After the analysis of the cell parameters extracted from the current-voltage (I-V) curves, possible origins of these effects were found to be: Passivation effects of the SnO2/CdS interface, blocking of impurities diffusion or improvement of the band alignment.

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Materials

Tập 11 Số 10

1788

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