Low Field Transport Properties of Two-Dimensional Electron Gas in Selectively Doped N-AlGaAs/GaInAs/GaAs Pseudomorphic Structures

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Abstract
In order to clarify the low field transport properties of two-dimensional electron gas (2DEG) in selectively doped (SD) AlGaAs/GaInAs/GaAs pseudomorphic structures, electron effective mass as well as electron scattering mechanisms were investigated using molecular beam epitaxially grown SD-Al0.3Ga0.7As/Ga0.87In0.13As/GaAs structures. Temperature dependence of Shubnikov-de Haas oscillation showed that the effective mass of 2DEG was greater than that of a bulk alloy. Enhancement of the effective mass quantitatively agrees with that expected from the effect of strain and nonparabolicity. The 2DEG mobilities were measured by Hall measurements as a function of carrier concentration, n s , as well as a function of temperature. At a low temperature range (< 40 K), mobility increased with increasing n s and saturated at a high n s region where virtually no temperature dependence was observed. Comparison of the mobility with that of AlGaAs/GaAs heterostructures and the results of the scattering theory revealed that the mobility at low temperatures can be quantitatively explained by the cluster scattering due to compositional nonuniformity in addition to the remote ionized impurity scattering.