Nonalloyed ohmic contacts, with contact resistances as low as 9 μΩ  cm2, are obtained to p++ GaP using Ni and Ti–Au. Very high p-type doping (5×1019 cm−3) is achieved in GaP using a growth temperature of 400 °C followed by an ex situ high-temperature rapid thermal anneal. The p-type dopant is beryllium and the films are grown by solid source molecular beam epitaxy equipped with a valved phosphorus cracker. A record high hole concentration (2×1019 cm−3) is reported in In0.49Ga0.51P by using a growth temperature of 350 °C.

Very high p-type doping is achieved in GaP and InxGa1−xP with Be in solid source molecular beam epitaxy equipped with a valved phosphorus cracker. Dependence of hole concentration on the growth temperature and on the Be flux during growth is studied for GaP. The hole concentration peaks at 3×1019 cm−3 for normal temperature (600 °C) growth. It is slightly higher at a lower growth temperature of 400 °C for the same Be flux. A higher hole concentration (5×1019 cm−3) is obtained by giving a high temperature rapid thermal anneal to this sample. A hole concentration of 2×1019 cm−3 is achieved in In0.49Ga0.51P by using a lower temperature growth (350 °C). To our knowledge, this is the highest reported hole concentration for any p-type dopant in In0.49Ga0.51P.