Back-Gated Field Effect in a Double Two-Dimensional Electron Gas Structure

Abstract

Selective ohmic-contacts were made to double two-dimensional electron gas (2DEG) layers spatially separated by 1000 Å in a GaAs–AlGaAs quantum well heterostructure. A HEMT-type device was fabricated by utilizing a surfaceside 2DEG layer as an active channel and substrate-side 2DEG as a backside gate conductor. The transconductance increased by 50% with an applied back-gate bias as low as 1 V. This bias is about three orders of magnitude lower than any previously reported back-gated HEMT structures. Hot-electron transfer between the two 2DEG layers, induced by the applied electric field, was also observed.