Phys. Rev. B 77, 235307 (2008) [9 pages]Transport anisotropy in In0.75Ga0.25As two-dimensional electron gases induced by indium concentration modulationReceived 2 April 2008; published 12 June 2008 A pronounced anisotropy is observed in the low-temperature mobility of a two-dimensional electron gas formed in an In0.75Ga0.25As/In0.75Al0.75As quantum well grown on a GaAs substrate. We show that the mobility differences along [011] and [011̅ ] directions are mainly due to In concentration modulations. Spatially resolved photoemission measurements show an asymmetric indium concentration modulation, correlated with the surface morphology observed by atomic force microscopy. A theoretical model considering conduction band energy modulations agrees well with the transport measurements. The identification of this mobility limiting mechanism allowed us to design and grow higher quality two-dimensional electron gases, needed for high indium content InGaAs device fabrication. © 2008 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevB.77.235307
DOI:
10.1103/PhysRevB.77.235307
PACS:
73.63.Hs, 73.50.Bk, 73.61.Ey, 79.60.Bm
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