Monolithic integration of low-temperature-grown GaAs with a two-dimensional electron gas

摘要

A scheme is presented for the monolithic integration of low-temperature-grown gallium arsenide (LT-GaAs) with a two-dimensional electron gas. Pulsed terahertz (THz) emission (with a 3 THz bandwidth) is demonstrated from a LT-GaAs layer grown epitaxially above a GaAs-AlGaAs heterojunction containing a two-dimensional electron gas, using photoconductive antennae patterned on the LT-GaAs, and excited with 800 nm, 12 fs laser pulses. Electrical transport measurements of the two-dimensional electron gas at cryogenic temperatures, and in high magnetic fields, reveal quantum Hall behaviour. The THz emission characteristics of the LT-GaAs, and the transport properties of the two-dimensional electron gas demonstrate that this integrated approach compromises neither the quality of the LT-GaAs nor the two-dimensional electron gas, and indicate the potential of this monolithic integration for sub-picosecond electronic measurements of mesoscopic systems.