Effect of arsenic pressure on donor and acceptor concentration in Si doped MBE GaAs layers

The influence of As/Ga flux ratio on the transport and optical properties of high purity Si-doped MBE GaAs has been investigated using two arsenic cells alternately or simultaneously. When the As produced from one cell increases by one order of magnitude, the 77 K Hall mobility decreases from 127000 to 75000 cm 2 V -1 s -1 as the carrier concentration increases from 2.9×10 14 to 1.1×10 15 cm -3 . When two arsenic cells instead of a single one are used simultaneously at lower temperature, the Hall mobilities are around 10% lower for equivalent free carrier concentrations.