Undoped electron-hole bilayers in a GaAs/AlGaAs double quantum well

The authors present the fabrication details of completely undoped electron-hole bilayer devices in a GaAsAlGaAs double quantum well heterostructure with a 30 nm barrier. These devices have independently tunable densities of the two-dimensional electron gas and two-dimensional hole gas. The authors report four-terminal transport measurements of the independently contacted electron and hole layers with balanced densities from 1.2× 1011 cm-2 down to 4× 1010 cm-2 at T=300 mK. The mobilities can exceed 1× 106 cm2 V-1 s-1 for electrons and 4× 105 cm2 V-1 s-1 for holes. © 2007 American Institute of Physics.