On-chip Hybrid Superconducting-Semiconducting Quantum Circuit

In this paper, we experimentally demonstrate a hybrid superconducting-semiconducting circuit consisting of eight planar and ballistic Nb-In_0.75Ga_0.25As-Nb Josephson junctions. E-beam lithography was used to fabricate the Josephson junctions on an InGaAs chip. In contrast to our previous studies on long junctions that were fabricated by photolithography, in this study, we observe the induced superconductivity in an In_0.75Ga_0.25 As quantum well at higher temperatures, between T = 0.3 and 1 K (³He cryostat temperature range). The induced superconducting gap of Δ_ind = 0.65 meV was measured at lowest base temperature T = 300 mK. The effect of temperature and magnetic fields B on the induced superconductivity are presented. Our results suggest that our In _0.75Ga_0.25 As heterostructure is a promising scalable material system for quantum processing and computing applications.