On the influence of indium addition on the mechanical properties of gallium arsenide at room temperature

¹ CEMES-CNRS, BP 4347, 29 rue Jeanne Marvig, 31055 Toulouse Cedex 4, France
² LPMC, Département de Physique, INSA, Complexe Scientifique de Rangueil, 31077 Toulouse Cedex 4, France

Corresponding author: levade@cemes.fr

Received: 13 June 1997
Revised: 3 October 1997
Accepted: 18 November 1997
Published online: 15 February 1998

Abstract

Indentations have been performed on (001) faces of indium alloyed GaAs crystals in darkness and under infrared illumination. The Vickers hardness was measured and the dislocation microstructure around the indents observed by high voltage transmission electron microscopy. A softening effect of indium is evidenced by comparison with the Vickers hardness obtained in the same conditions on undoped GaAs. No significant influence of indium on the dislocation microstructure resulting from indentation in darkness is noted. Indentation under infrared illumination does not reveal any macroscopic photoplastic effect; however, a modification of dislocation microstructure is observed. Whatever the experimental conditions, dislocations appear to experience strong lattice friction. The softening effect of indium addition and the enhanced dislocation mobilities under infrared illumination are discussed in the framework of dislocation glide governed by the Peierls mechanism.