HIGH-QUALITY 2-DIMENSIONAL ELECTRON-GAS IN ALXGA1-XAS GAAS HETEROSTRUCTURES BY LP-OMVPE

Combination of high mobility and high sheet carrier density in AlxGa1-xAs/GaAs two-dimensional electron gas (2DEG) elements was obtained by low-pressure organometallic vapor phase epitaxy (OMVPE). The sheet charge densities (n(s)) and mobilities (mu) at 77 K are 1.2 x 10(12)/cm2 and 90 000 cm2/V . s for single-channel, and 2.0 x 10(12)/cm2 and 64 500 cm2/V . s for double-channel elements, respectively. Strong correlations between the photoluminescence spectrum of the AlxGa1-xAs layers and the 2DEG mobility were found. The 2DEG elements were used as mixers and detectors at millimeter waves. Mixing at 94 GHz with a 1.7-GHz IF bandwidth and detection of signals as high as 238 GHz under a magnetic field were achieved with these devices.