---
_id: '18076'
abstract:
- lang: eng
  text: "The new era of Ge has opened up new possibilities in quantum computing. The
    maturity of Ge\r\nspin qubits is unquestioned, while hybrid semiconductor-superconductor
    Ge circuits are on track\r\nto enter the game. Gate-tunable transmons (gatemons)
    employing semiconductor Josephson\r\njunctions have recently emerged as building
    blocks for such hybrid quantum circuits. In this\r\nthesis, we present a gatemon
    fabricated in planar Germanium. We induce superconductivity\r\nin a two-dimensional
    hole gas by evaporating aluminum atop a thin spacer, which separates\r\nthe superconductor
    from the Ge quantum well. The Josephson junction is then integrated\r\ninto an
    Xmon circuit and capacitively coupled to a transmission line resonator. We showcase\r\nthe
    qubit tunability in a broad frequency range with resonator and two-tone spectroscopy.\r\nTime-domain
    characterizations reveal energy relaxation and coherence times up to 75 ns. Our\r\nresults,
    combined with the recent advances in the spin qubit field, pave the way towards
    novel\r\nhybrid and protected qubits in a group IV, CMOS-compatible material."
acknowledged_ssus:
- _id: NanoFab
- _id: M-Shop
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Oliver
  full_name: Sagi, Oliver
  id: 71616374-A8E9-11E9-A7CA-09ECE5697425
  last_name: Sagi
citation:
  ama: Sagi O. Hybrid circuits on planar Germanium. 2024. doi:<a href="https://doi.org/10.15479/at:ista:18076">10.15479/at:ista:18076</a>
  apa: Sagi, O. (2024). <i>Hybrid circuits on planar Germanium</i>. Institute of Science
    and Technology Austria. <a href="https://doi.org/10.15479/at:ista:18076">https://doi.org/10.15479/at:ista:18076</a>
  chicago: Sagi, Oliver. “Hybrid Circuits on Planar Germanium.” Institute of Science
    and Technology Austria, 2024. <a href="https://doi.org/10.15479/at:ista:18076">https://doi.org/10.15479/at:ista:18076</a>.
  ieee: O. Sagi, “Hybrid circuits on planar Germanium,” Institute of Science and Technology
    Austria, 2024.
  ista: Sagi O. 2024. Hybrid circuits on planar Germanium. Institute of Science and
    Technology Austria.
  mla: Sagi, Oliver. <i>Hybrid Circuits on Planar Germanium</i>. Institute of Science
    and Technology Austria, 2024, doi:<a href="https://doi.org/10.15479/at:ista:18076">10.15479/at:ista:18076</a>.
  short: O. Sagi, Hybrid Circuits on Planar Germanium, Institute of Science and Technology
    Austria, 2024.
corr_author: '1'
date_created: 2024-09-16T12:58:36Z
date_published: 2024-09-18T00:00:00Z
date_updated: 2025-10-15T06:31:48Z
day: '18'
ddc:
- '539'
degree_awarded: PhD
department:
- _id: GradSch
- _id: GeKa
doi: 10.15479/at:ista:18076
ec_funded: 1
file:
- access_level: open_access
  checksum: d01d0e2846c2f3ac5bb14d321554a4cd
  content_type: application/pdf
  creator: osagi
  date_created: 2024-09-18T14:13:01Z
  date_updated: 2024-09-18T14:13:01Z
  file_id: '18093'
  file_name: OliverSagi_Thesis_pdfa.pdf
  file_size: 86679095
  relation: main_file
  success: 1
- access_level: local
  checksum: 0543f473d509ee545f4ed3a56f742f4b
  content_type: application/x-zip-compressed
  creator: osagi
  date_created: 2024-09-18T14:14:02Z
  date_updated: 2024-09-19T09:20:33Z
  file_id: '18094'
  file_name: Thesis_OliverSagi.zip
  file_size: 172098524
  relation: source_file
file_date_updated: 2024-09-19T09:20:33Z
has_accepted_license: '1'
language:
- iso: eng
month: '09'
oa: 1
oa_version: Published Version
page: '111'
project:
- _id: bd8bd29e-d553-11ed-ba76-f0070d4b237a
  grant_number: P36507
  name: Merging spin and superconducting qubits in planar Ge
- _id: c0977eea-5a5b-11eb-8a69-a862db0cf4d1
  grant_number: I05060
  name: High impedance circuit quantum electrodynamics with hole spins
- _id: 262116AA-B435-11E9-9278-68D0E5697425
  name: Hybrid Semiconductor - Superconductor Quantum Devices
- _id: 237E5020-32DE-11EA-91FC-C7463DDC885E
  call_identifier: H2020
  grant_number: '862046'
  name: TOPOLOGICALLY PROTECTED AND SCALABLE QUANTUM BITS
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '17202'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Georgios
  full_name: Katsaros, Georgios
  id: 38DB5788-F248-11E8-B48F-1D18A9856A87
  last_name: Katsaros
  orcid: 0000-0001-8342-202X
title: Hybrid circuits on planar Germanium
tmp:
  image: /images/cc_by_nc_sa.png
  legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
  name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
    BY-NC-SA 4.0)
  short: CC BY-NC-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2024'
...