Tunable all epitaxial semimetal-semiconductor Schottky diode system: ErAs on InAlGaAs

We report the growth, fabrication, and electrical properties of a fully epitaxial semimetal-semiconductor Schottky diode materials system: ErAs on InAlGaAs. The coherent, thermodynamically stable, lattice-matched interface eliminates oxide and interfacial third phases, making the Schottky barrier height and associated electrical parameters dependent on the fundamental molecular bonding (e.g., interface dipoles) rather than unintentional extrinsic effects. ErAs:InAlGaAs diodes thus have highly tunable properties; by adjusting composition, doping, and interface type, the Schottky barrier height is tunable from ∼100meVto∼620meV, short circuit responsivity is tunable from 0.5to19A∕W, differential resistance is tunable from 103to1010Ωμm2, and capacitance is tunable from 0.4to2fF∕μm2. Rectification of a rf source has been demonstrated up to 20GHz. ErAs:InAlGaAs is thus a very promising materials system for design of an upper mm-wave, zero-bias, square-law detector with a significantly reduced noise floor.