Mobility of the two-dimensional electron gas at selectively doped n -type As/GaAs heterojunctions with controlled electron concentrations
- 15 June 1986
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 33 (12), 8291-8303
- https://doi.org/10.1103/physrevb.33.8291
Abstract
We describe our systematic study of the two-dimensional electron mobilities μ of n-type As/GaAs heterojunctions, in particular their dependence on the electron concentration and the temperatures T, in a variety of field-effect transistors in which the impurity locations are precisely controlled to vary μ over the wide range of 5× to 1.5× /V s. It is found that μ increases with increasing in the temperature range of 10 to 300 K. The measured mobilities are compared with theoretical calculations. The observed dependence of μ on at low temperatures is shown to be in excellent agreement with the theory of ionized-impurity scattering, whereas the high-temperature data disagree with the existing theory of polar-optical phonon scattering. A quantitative study has been successfully made on the effect of an undoped As spacer layer, which enhances not only μ itself but also the slope in logμ-log characteristics. The presence of both positive and negative temperature dependences of μ at low temperatures (T<40 K) is noted, and its connection with the effects of nondegeneracy and lattice scattering is also discussed.
Keywords
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