The effect of threading dislocations upon the optical and electrical properties of GaAs hetero-epitaxial layers on (001)Si was investigated. Charged deep states acted as scattering centers for electrons; thus affecting the electron mobility at low temperatures. The electric field which arose from charged dislocations caused an enhanced optical absorption at wavelengths near to the fundamental absorption edge. The mean charge of the threading dislocations was found to be relatively high. A model was described which attributed this effect to a regular arrangement of α-type 60º dislocations at extended twin defects; which were absent from GaAs/Si.

The Effect of Threading Dislocations on Optical Absorption and Electron Scattering in Strongly Mismatched Heteroepitaxial III–V Compound Semiconductors on Silicon. E.Peiner, A.Guttzeit, H.H.Wehmann: Journal of Physics - Condensed Matter, 2002, 14[48], 13195-201