Two deep electron traps induced by lattice mismatch in relaxed GaAs1−xSbx layers (x=0% to 3%) grown by liquid phase epitaxy (LPE) on GaAs substrates have been revealed by means of deep-level transient spectroscopy. One of the traps, that shows nonstandard, logarithmic capture kinetics and whose energy level is tied to the valence-band edge, has been related to electron states associated with α dislocations. The other trap has been attributed to the EL2 defect and possible reasons of its unexpected formation in the LPE-grown layers are briefly discussed.

Optical and electrical measurements of GaAs layers grown by liquid phase epitaxy with different amounts of Yb metal (0–1000 ppm) added to the Ga solution are reported. The presence of Yb during growth causes strong suppression of all donor-related optical transitions due to the effective removal of donors, as judged from Hall effect data. We have not found any appreciable increase of the background acceptor concentration during conductivity conversion from n-type to p-type, and thus conclude that dominant donor gettering occurs already in the Ga solution. No Yb3+ (4f 13)-related emission was detected in the as-grown GaAs layers.

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