Hardy, W.J.W.J.HardySu, Y.-H.Y.-H.SuChuang, Y.Y.ChuangMaurer, L.N.L.N.MaurerBrickson, M.M.BricksonBaczewski, A.A.BaczewskiJIUN-YUN LILu, T.-M.T.-M.LuLuhman, D.R.D.R.Luhman2021-05-052021-05-05201919386737https://www.scopus.com/inward/record.url?eid=2-s2.0-85077205052&partnerID=40&md5=e8da95dbf1b2ff2ce664f9f21d2f1a94https://scholars.lib.ntu.edu.tw/handle/123456789/559060In the field of semiconductor quantum dot spin qubits, there is growing interest in leveraging the unique properties of hole-carrier systems and their intrinsically strong spin-orbit coupling to engineer novel qubits. Recent advances in semiconductor heterostructure growth have made available high quality, undoped Ge/SiGe quantum wells, consisting of a pure strained Ge layer flanked by Ge-rich SiGe layers above and below. These quantum wells feature heavy hole carriers and a cubic Rashba-type spin-orbit interaction. Here, we describe progress toward realizing spin qubits in this platform, including development of multi-metal-layer gated device architectures, device tuning protocols, and charge-sensing capabilities. Iterative improvement of a three-layer metal gate architecture has significantly enhanced device performance over that achieved using an earlier single-layer gate design. We discuss ongoing, simulation-informed work to fine-tune the device geometry, as well as efforts toward a single-spin qubit demonstration. ©The Electrochemical SocietyMetals; Nanocrystals; Nanoelectronics; Network architecture; Quantum optics; Qubits; Semiconducting germanium; Semiconductor quantum dots; Semiconductor quantum wells; Si-Ge alloys; Silicon; Charge sensing; Device geometries; Device performance; Gate-defined quantum dots; Ge/sige quantum wells; Iterative improvements; Rashba-type spin-orbit; Semiconductor heterostructure; Spin orbit couplingconference paper10.1149/09201.0017ecst2-s2.0-85077205052