Hole mobility in Al xGa 1-xSb grown by metalorganic chemical vapor deposition

The temperature dependence of the hole mobilities of Al _xGa _1-xSb films in the regime 0≤x≤0.25 has been examined by Van der Pauw-Hall measurements. The films have been grown by metalorganic chemical vapor deposition on Si-GaAs substrates using TMAl, TMGa, TMSb precursors. The mobility decreases sharply when a small amount of Al in the range 0<x<0.025 is incorporated into GaSb. The temperature dependence of mobility was analyzed using a model with contributions from various scattering mechanisms. At a low-temperature (<100 K), the mobility decreased due to a contribution from ionized-impurity scattering and in a high-temperature region (>100 K), the same effect was due to lattice phonon scattering. At 300 and 77 K, the alloy scattering is the most important mechanism in Al _xGa _1-xSb ternaries, however the temperature dependence of alloy scattering is less pronounced as the temperature decreases.