CALCULATION OF DISPLACEMENT FIELDS AND SIMULATION OF HRTEM IMAGES OF DISLOCATIONS IN SPHALERITE TYPE A(III)B(V) COMPOUND SEMICONDUCTORS

摘要

The displacement fields of different kinds of both perfect and dissociated dislocations have been calculated for an isotropic continuum, and by means of linear elasticity. Additionally, the corresponding HRTEM images have been simulated by the well-established EMS program package in order to predetermine the structural aspects of dislocations, and then to compare it with experimental HRTEM micrographs. The latter ones resulted from plastically deformed GaP single crystals and InAs/(001)GaAs single epitaxial layers. It could be established that using the simple approach of linear elasticity and isotropy results can be obtained which correspond well to the experimental images. So, the structure of various Shockley partial dislocations bounding a stacking fault can be detected unambiguously. The splitting behaviour of perfect 30 degrees dislocations (separation into a 0 degrees and 60 degrees partial) and 90 degrees dislocations (separation into two 60 degrees partials) both with line direction along [112]; 60 degrees dislocations (separation into 30 degrees/90 degrees and 90 degrees/30 degrees configuration) and screw dislocations (separation into two 30 degrees partials) along [110] are discussed in the more detail. Moreover, the undissociated sessile Lomer dislocation, glissile 60 degrees dislocation and edge dislocation have been considered too. [References: 47]