CONCERNING THE IDENTITY OF THE PREDOMINANT ACCEPTORS IN GASB
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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The uniformity of samples of GaSb prepared in different laboratorie from different starting materials over an extended period suggested that the acceptors in the purest available GaSb were predominantly lattice defects associated with deviations from stoichiometry. In order to obtain additional evidence concerning the nature of the acceptors, an analysis was made of samples of GaSb cut from a single crystal which contained free hole concentrations from 1.25 to 1.55 x 10 to the 17th powercc at room temperature. A spark source mass spectrograph was used which was capable of detecting any impurity element present at concentrations exceeding 1 x 10 to the 16th powercc, provided no interference was produced between spectral lines by different isotopes and the proportion of residual gas ions striking the photographic plate were negligible. The analytical results appreciably increased the probability that the predominant acceptors in the purest available GaSb are lattice defects rather than impurity atoms. The suggestion is made that if the predominant acceptors are actually lattice defects that these defects may be Ga vacancies.