LOCALIZED 2-DIMENSIONAL ELECTRON-GAS FORMATION BY FOCUSED SI ION-BEAM IMPLANTATION INTO GAAS ALGAAS HETEROSTRUCTURES

We have demonstrated the localized formation of a two-dimensional electron gas (2DEG) using focused Si ion beam implantation (100 keV) into undoped GaAs/AlGaAs heterostructures. We found that to achieve a good-quality 2DEG without also forming a 3DEG it is essential to use a double instead of a single interface heterostructure. The low-temperature mobility of the 2DEG was as high as 1.0×104 cm2/V s at a carrier concentration of 1×1012 cm-2. This 2DEG mobility in the double heterostructure was a factor of 3 larger than the 2DEG mobility in the single heterostructures.