R. Basco et al., ULTRAHIGH MOBILITY 2-DIMENSIONAL ELECTRON-GAS IN ALXGA1-XAS GAAS HETEROSTRUCTURES BY ORGANOMETALLIC VAPOR-PHASE EPITAXY/, Applied physics letters, 63(14), 1993, pp. 1960-1962
Ultrahigh mobility AlxGa1-xAs/GaAs two-dimensional electron gas (2DEG)
structures were grown by conventional low-pressure organometallic vap
or phase epitaxy (LP-OMVPE). We achieved maximum mobilities of 766 000
cm2/V s at 2.2 K and 171 000 cm2/V s at 77 K after exposure to light
(to our knowledge, the highest ever by OMVPE growth), with a sheet car
rier density of 4.9 X 10(11)/cm2. The high-mobility structures were ob
tained by either growing an AlGaAs-related buffer underneath the 2DEG
structure or preconditioning of the reactor with an undoped AlGaAs run
. The dark mobilities of samples grown with the preconditioning proced
ures and without the AlGaAs-related buffer are much higher than those
with the buffer.