High-quality two-dimensional electron gas in Al/sub x/Ga/sub 1-x/As/GaAs heterostructures by LP-OMVPE

A combination of high mobility and high sheet carrier density in Al/sub x/Ga/sub 1-x/As/GaAs two-dimensional electron gas (2DEG) elements was obtained by low-pressure organometallic vapor phase epitaxy (OMVPE). The sheet charge densities (n/sub s/) and mobilities ( mu ) at 77 K are 1.2*10/sup 12//cm/sup 2/ and 90000 cm/sup 2//V-s for single-channel, and 2.0* 10/sup 12//cm/sup 2 /and 64500 cm/sup 2//V-s for double-channel elements, respectively. Strong correlations between the photoluminescence spectrum of the Al/sub x/Ga/sub 1-x/As layers and the 2DEG mobility were found. The 2DEG elements were used as mixers and detectors at millimeter wavelengths. 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.<
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