Undoped high mobility two-dimensional hole-channel GaAs/Al _xGa_1-xAs heterostructure field-effect transistors with atomic-layer-deposited dielectric

The authors have fabricated undoped p -channel GaAs Alx Ga1-x As heterostructure field-effect transistors with nearly ideal drain current-voltage characteristics, using atomic-layer-deposited Al2 O3 as the dielectric, and measured their transport properties. At 0.3 K, the densities and mobilities of the two dimensional holes can be tuned up to 2.9× 1011 cm2 and 6.4× 105 cm2 V s, respectively. The variable density high mobility two-dimensional hole system provides a large parameter space for the study of two-dimensional physics.