Schottky contact between metal and two-dimensional electron gas: device applications to low-noise optical detectors

The current-voltage behaviour of a modified metal-semiconductor-metal (MSM) structure based on direct contact to an AlGaAs-GaAs heterojunction is presented. An analytical description of Schottky contact between metal and the two-dimensional electron gas (2-DEG) and its effects on current transport are investigated to better understand device operation. Thermionic emission calculations lead to a barrier enhancement factor of exp(-E/sub 0//k/sub B/T). The new device demonstrates reduction in dark current as well as higher responsivity and lower reach-through voltage.