P-TYPE DOPING OF GASB BY GE AND SN GROWN BY MOLECULAR-BEAM EPITAXY

p-type doping of molecular beam epitaxy grown GaSb by Ge and Sn has been demonstrated. Both impurities are well behaved with demonstrated free acceptor concentrations as high as 2 x 10(19) cm-3 for Ge and 5 x 10(18) cm-3 for Sn. In addition reflection high-energy electron diffraction measurements during growth indicate that Sn segregation which is common in GaAs does not occur in GaSb. The absence of Sn segregation as well as the p-type nature of Ge and Sn dopants is attributed to the large covalent bond radius of Sb. These dopants are important since they provide an excellent alternative to Be for p-type doping of Sb based materials.