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The Production of Doped Amorphous GaAs by Co-Sputtering With Mo

Published online by Cambridge University Press:  22 February 2011

S. Najar
Affiliation:
Faculté des Sciences et Techniques de St-JéromeLab. de PhotoélectricitéEquipe Matériaux Amorphes13, rue Henri Poincaré, 13397 Marseille Cedex 13, France.
K. Sedeek
Affiliation:
Faculté des Sciences et Techniques de St-JéromeLab. de PhotoélectricitéEquipe Matériaux Amorphes13, rue Henri Poincaré, 13397 Marseille Cedex 13, France.
H. Carchano
Affiliation:
Faculté des Sciences et Techniques de St-JéromeLab. de PhotoélectricitéEquipe Matériaux Amorphes13, rue Henri Poincaré, 13397 Marseille Cedex 13, France.
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Abstract

Stoichiometric amorphous GaAs films with intrinsic properties have beer produced by R.F. Sputtering in pure argon at high substrate temperature of 290°C. The electronic and the optical properties of this material have been modified by the molybdenium co-sputtering. This paper reports: on several modified material parameters including the electrical conductivity, thermal activation energy and optical gap. Atomic Mo concentrations up to 1.24% have been investigated. It is observed that the room temperature conductivity can be controlled over about six orders of magnitude, which corresponds to a shift in the Fermi level of 0.45 eV towards the conduction band edge. For optical parameters, the optical gap has been reduced by 0.1 eV. An additional absorption tail due to localized states introduced by doping atoms is observed. It is concluded that our a-GaAs have the main requirement, i. e low density of defect gap states, for effective doping with analogy to a-Si prepared either by glow discharge or by sputtering in argon-hydrogen plasma.

Type
Research Article
Copyright
Copyright © Materials Research Society 1985

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References

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