InGaAs superconducting JFET's with Nb electrodes

Abstract

Summary form only given. The authors have fabricated InGaAs junction FETs with Nb source and drain electrodes with submicrometer spacings. The devices exhibit gate-controlled supercurrents as large as 8 mA/mm at 4.2 K. This value of controlled supercurrent is larger than any previously reported for superconducting field-effect devices. The channel material was n-type In0.53Ga0.47As, epitaxially grown by molecular beam epitaxy on InP substrates. Gate control was achieved using a p-n junction which was buried below the channel. This structure allowed the Nb superconductor to be deposited directly onto the freshly grown channel layer to insure a clean superconductor-semiconductor contact, which is essential for obtaining optimum superconducting properties. The superconducting electrodes were patterned by reactive ion etching.