Growth and characterization of high current density, high-speed InAs/AlSb resonant tunneling diodes

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Abstract
High quality resonant tunneling diodes have been fabricated from the InAs/AlSb material system (InAs quantum well and cladding layers, AlSb barriers) on (100)GaAs substrates. A diode with a 6.4-nm-thick InAs quantum well and 1.5-nm-thick AlSb barriers yielded a room-temperature peak current density of 3.7×105 A cm−2 and peak-to-valley current ratio of 3.2. This corresponds to an available current density of 2.6×105 A cm−2, which is comparable to that of the best In0.53Ga0.47As/AlAs diodes grown on lattice-matched substrates and is three times higher than that of the best GaAs/AlAs diode reported to date. These results were obtained in spite of a 7.2% lattice mismatch between the InAs epilayers and the GaAs substrates, which leads to a measured threading dislocation density of roughly 109 cm−2. The experimental peak voltage and current density are in good agreement with theoretical calculations based on a stationary-state transport model with a two-band envelope function approximation.