Research on Semiconductors at Cryogenic Temperatures
Final rept. 1 Jul 1985-18 Jun 1988
WESTINGHOUSE RESEARCH AND DEVELOPMENT CENTER PITTSBURGH PA
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The Hall mobility and magnetoresistance of selectivity doped heterostructures of SixGe1-xGe prepared by molecular beam epitaxy MBE have been studied in the temperature range 1.5 T 300K. Either Al or B was used to dope the alloy p-type. Evidence was found in the B-doped samples with x 0.5 that a 2DHG is formed in the Ge at the heterointerface. The mobility at T 4.2K in a sample with an undoped alloy spacer layer of 4 nm was micro H 3200 sq. cm.V-sec and in other samples was found to decrease with spacer layer thickness. Shubnikov-de Haas oscillations were observed at T 1.5K with the magnetic field normal to the interface, but not with the field parallel to it. The oscillation period yields a surface charge density of 2 x 10 to the 12thsq. cm. in reasonable agreement with the value of 3 x 10 to the 12thsq. cm. obtained by Hall measurements. Silicon compounds, Germanium compounds.
- Inorganic Chemistry