Epitaxial superconductor-semiconductor two-dimensional systems for superconducting quantum circuits

Qubits on solid state devices could potentially provide the rapid control necessary for developing scalable quantum information processors. Materials innovation and design breakthroughs have increased functionality coherence of qubits substantially over past two decades. Here, we show by improving interface between InAs as a semiconductor Al superconductor, one can reliably fabricate voltage-controlled Josephson junction field effect transistor (JJ-FET) that be used tunable qubits, resonators, coupler switches. We find bandgap engineering is crucial in realizing two-dimensional electron gas near surface. In addition, how coupling layer superconducting contacts affect qubit properties. present anharmonicity strengths from two-photon absorption level system fabricated with JJ-FET.