Selectively δ-doped quantum well transistor grown by gas-source molecular-beam epitaxy

We report electrical measurements on structures generated by δ doping the AlGaAs barriers of a GaAs quantum well. These structures are made unique by quantum size effects that occur both in the δ-doped barrier and in the GaAs well. Both the Hall-effect and capacitance-voltage measurements reveal that high-density, 4×1012 cm−2, two-dimensional electron gas forms in the well along with good mobility. We fabricate field-effect transistors with this structure to obtain transconductances of 300 mS/mm.