Superconducting junctions using a 2DEG in a strained InAs quantum well inserted into an InAlAs/InGaAs MD structure

A newly fabricated three-terminal Josephson junction is coupled with a two-dimensional electron gas (2DEG) in a strained InAs quantum well inserted into an InAlAs/InGaAs modulation-doped structure. The 2DEG is confined in the InAs quantum well and has a maximum mobility of 155000 cm/sup 2//Vs at a sheet-carrier density of 1.86/spl times/10/sup 12/ cm/sup -2/ at 10 K. The supercurrent flows through the 2DEG and can be controlled by adjusting the gate voltage. The critical current and normal resistance are measured as a function of the gate voltage, and the sheet-carrier density dependence of the critical current is obtained. We also measure the temperature dependence of the critical current at different gate voltages. The results indicate that, when using this junction, the superconducting characteristics can range between the clean and dirty limits.<>