A predominant deep level with an activation energy of 0.23 to 0.26eV was detected, by means of admittance spectroscopy, in SnTe-doped GaSb layers which had been grown directly onto GaAs substrates by using molecular beam epitaxy. The Sb4/Ga flux ratio was found to affect the Hall mobility and the concentration of the deep level in a similar way. An optimum beam equivalent pressure ratio of about 7, for GaSb which was grown at 550C, was suggested to be the lowest ratio at which an Sb-stabilized surface reconstruction could be maintained. This electron level was usually detected in n-type (SnTe-, S- or Te-doped) GaSb, but not in undoped p-type GaSb. It was concluded that this level was not a simple native defect, but might be related to the impurity that was used to dope GaSb in order to make it n-type.

J.F.Chen, N.C.Chen, H.S.Liu: Japanese Journal of Applied Physics, 1996, 35[2-7A], L813-5