Limits to mobility in InAs quantum wells with nearly lattice-matched barriers

Abstract

The growth and density dependence of the low temperature mobility of a series of two-dimensional electron systems confined to unintentionally doped, low extended defect density InAs quantum wells with $\mathrm{A}{\mathrm{l}}_{1\ensuremath{-}x}\mathrm{G}{\mathrm{a}}_{x}\mathrm{Sb}$ barriers are reported. The electron-mobility-limiting scattering mechanisms were determined by utilizing dual-gated devices to study the dependence of mobility on carrier density and electric field independently. Analysis of possible scattering mechanisms indicate the mobility was limited primarily by rough interfaces in narrow quantum wells and a combination of alloy disorder and interface roughness in wide wells at high carrier density within the first occupied electronic subband. At low carrier density, the functional dependence of mobility on carrier density provided evidence of Coulombic scattering from charged defects. A gate-tuned electron mobility exceeding $750\phantom{\rule{0.16em}{0ex}}000\phantom{\rule{4pt}{0ex}}\mathrm{c}{\mathrm{m}}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{V}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$ was achieved at a sample temperature of 2 K.