02683ntm 22004217a 4500999001900000003000800019005001700027008004100044040000800085100002400093245007000117260002200187500001100209505001300220505002000233505002100253505002500274505001900299505002000318505002600338505001900364505004100383505004200424505004500466505003700511505004400548505004600592505002900638505001700667505002600684505003600710505002800746505001500774520133100789856004502120942000802165952008802173 c374017d374017AT-ISTA20190813152041.0190813s2018 au ||||| m||| 00| 0 eng d cIST aVukusic, Lada94469 aCharge sensing and spin relaxation times of holes in Ge hut wires bIST Austriac2018 aThesis aAbstract aAcknowledgments aAbout the Author aList of Publications aList of Tables aList of Figures aList of Abbreviations a1 Introduction a2 Self-assembled SiGe nanostructures a3 Basics of transport in quantum dots a4 Fabrication and measurement techniques a5 Charge sensing in Ge hut wires a6 Hole tunnelling times in Ge hut wires a7 Single-shot readout of hole spins in Ge a8 Conclusion and outlook aBibliography aA Fabrication details aB Electrical circuit components aC Rise time calculation aD Software aA qubit, a unit of quantum information, is essentially any quantum mechanical two-level system which can be coherently controlled. Still, to be used for computation, it has to fulfill criteria. Qubits, regardless of the system in which they are realized, suffer from decoherence. This leads to loss of the information stored in the qubit. The upper bound of the time scale on which decoherence happens is set by the spin relaxation time. In this thesis I studied a two-level system consisting of a Zeeman-split hole spin confined in a quantum dot formed in a Ge hut wire. Such Ge hut wires have emerged as a promising material system for the realization of spin qubits, due to the combination of two significant properties: long spin coherence time as expected for group IV semiconductors due to the low hyperfine interaction and a strong valence band spin-orbit coupling. Here, I present how to fabricate quantum dot devices suitable for electrical transport measurements. Coupled quantum dot devices allowed the realization of a charge sensor, which is electrostatically and tunnel coupled to a quantum dot. By integrating the charge sensor into a radio-frequency reflectometry setup, I performed for the first time single-shot readout measurements of hole spins and extracted the hole spin relaxation times in Ge hut wires. uhttps://doi.org/10.15479/AT:ISTA:TH_1047 2ddc 00102ddc4070aLIBbLIBd2019-08-13pAT-ISTA#001869r2021-08-26w2019-08-13yBOOK