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Full-Text Articles in Physics

Evolution Of The Band Structure Of Β-In2 S3−3x O3x Buffer Layer With Its Oxygen Content, N. Barreau, S. Marsillac, J. C. Bernède, L. Assmann May 2003

Evolution Of The Band Structure Of Β-In2 S3−3x O3x Buffer Layer With Its Oxygen Content, N. Barreau, S. Marsillac, J. C. Bernède, L. Assmann

Electrical & Computer Engineering Faculty Publications

The evolution of the band structure of β-In2 S3−3x O3x (BISO) thin films grown by physical vapor deposition, with composition x, is investigated using x-ray photoelectron spectroscopy. It is shown that the energy difference between the valence-band level and the Fermi level remains nearly constant as the optical band gap of the films increases. As a consequence, the difference between the conduction band level and the Fermi level increases as much as the optical band gap of the films. The calculation of the electronic affinity [ ] of the BISO thin films shows that it decreases linearly from 4.65 …


Bandtail Limits To Solar Conversion Efficiencies In Amorphous Silicon Solar Cells, Kai Zhu, Weining Wang, Eric A. Schiff, Jianjun Liang, S. Guha Jan 2003

Bandtail Limits To Solar Conversion Efficiencies In Amorphous Silicon Solar Cells, Kai Zhu, Weining Wang, Eric A. Schiff, Jianjun Liang, S. Guha

Physics - All Scholarship

We describe a model for a-Si:H based pin solar cells derived primarily from valence bandtail properties. We show how hole drift-mobility measurements and measurements of the temperature-dependence of the open-circuit voltage VOC can be used to estimate the parameters, and we present VOC(T) measurements. We compared the power density under solar illumination calculated with this model with published results for as-deposited a-Si:H solar cells. The agreement is within 4% for a range of thicknesses, suggesting that the power from as-deposited cells is close to the bandtail limit.


Amorphous Silicon Based Solar Cells, Xunming Deng, Eric A. Schiff Jan 2003

Amorphous Silicon Based Solar Cells, Xunming Deng, Eric A. Schiff

Physics - All Scholarship

Crystalline semiconductors are very well known, including silicon (the basis of the integrated circuits used in modern electronics), Ge (the material of the first transistor), GaAs and the other III-V compounds (the basis for many light emitters), and CdS (often used as a light sensor). In crystals, the atoms are arranged in near-perfect, regular arrays or lattices. Of course, the lattice must be consistent with the underlying chemical bonding properties of the atoms. For example, a silicon atom forms four covalent bonds to neighboring atoms arranged symmetrically about it. This “tetrahedral” configuration is perfectly maintained in the “diamond” lattice of …