Highly Sensitive p-GaAsSb/n-InAs Nanowire Backward Diodes for Low-Power Microwaves

Type-II p-GaAs0.6Sb0.4/n-InAs nanowire backward diodes (BWDs) were developed for ambient RF energy harvesting. Vapor-liquid-solid (VLS) growth method was used to grow nanowire segments on a GaAs(111)B substrate. For stable growth, n-GaAs nanowire segments were grown before growing p-GaAs0.6Sb0.4/n-InAs segments. The I-V characteristic of the diodes displayed large nonlinearity under zero bias condition, which is typical of backward diodes. The nanowire BWDs indicated linear detected voltages when a microwave input signal from 0.1 to 10 mu W was applied at 2.4 GHz. The diodes can operate at 2.4 GHz under zero bias. Impedance-matched voltage sensitivity of 370 kV/W was obtained for the nanowire BWDs. The obtained sensitivity value was higher than those of well-designed Schottky barrier diodes (SBDs).