Atomic-layer epitaxy of device-quality Al0.3Ga0.7As

We report on the recent growth by Atomic Layer Epitaxy (ALE) of device quality Al 0.3 Ga 0.7 As in a modified commercial reactor. A standard Emcore reactor was altered by the installation of baffles to prevent mixing of the reactant gas streams and a computer controlled servo motor to allow for a nonlinear rotation cycle. By varying the V/III ratio and the exposure time to the reactant gases it is possible to control the background carbon doping from high resistivity to p equals 1 X 10 20 cm -3 , without the need for an additional p-type source. Since low background doping was also achieved, silane was used to obtain n-type Al 0.3 Ga 0.7 As as high as n equals 1 X 10 18 cm -3 . The room temperature Hall mobility of the n-type Al 0.3 Ga 0.7 As films varied from 1200 to 3700 cm 2 /V(DOT)sec. Photoluminescence and preliminary doping results are presented and discussed.