Extremely High Mobility of Two-Dimensional Electron Gas in Selectively Doped GaAs/N-AlGaAs Heterojunction Structures Grown by MBE

Abstract

Selectively Si-doped GaAs/ N -AlGaAs heterojunction structures have been grown by MBE. Two-dimensional electron gas accumulating at the interface of the heterojunction showed mobilities as high as 69,000 cm 2 /Vs at 77 K and 100,000 cm 2 /Vs at 4.2 K, with a sheet electron concentration of 5.5×10 11 cm -2 , which are higher than any reported so far. An enhancementmode high electron mobility transistor (E-HEMT), which was first fabricated from the heterojunction material, showed a field effect mobility of 49,300 cm 2 /Vs at 77 K, suggesting that this heterojunction material has potential for application to low-power, high-speed integrated circuits.