Abstract
We engineer planar Ge/SiGe heterostructures for low disorder and quiet hole quantum dot operation by positioning the strained Ge channel 55 nm below the semiconductor/dielectric interface. In heterostructure field effect transistors, we measure a percolation density for two-dimensional hole transport of 2.1 × 1010 cm−2, indicative of a very low disorder potential landscape experienced by holes in the buried Ge channel. These Ge heterostructures support quiet operation of hole quantum dots and we measure an average charge noise level of at 1 Hz, with the lowest level below our detection limit . These results establish planar Ge as a promising platform for scaled two-dimensional spin qubit arrays.
Highlights
We engineer planar Ge/SiGe heterostructures for low disorder and quiet hole quantum dot operation by positioning the strained Ge channel 55 nm below the semiconductor/dielectric interface
The Ge quantum well (QW) was located remakarbly close to semiconductor/dielectric interface at a depth of only 22 nm[17]. While this shallow heterostructure showed an ultra-high maximum mobility exceeding 5×105 cm2/Vs, possibly due to passivation of surface impurities by tunneled carriers from the QW, a rather high percolation density pp = 1.2 × 1011 cm−2 was measured. This value is similar to the values reported for Si metaloxide semiconductor field effect transistors[22,23,24] and about twice the value reported in Si/SiGe QWs[25, 26]
Since the percolation density characterizes disorder at low densities, which is the typical regime for quantum dot operation, a significant development is still needed to make undoped Ge/SiGe heterostructures compatible with existing architectures for large-scale quantum information processing with quantum dots, all relying on highly uniform qubits that exhibit extremely low noise[16, 27]
Summary
We engineer planar Ge/SiGe heterostructures for low disorder and quiet hole quantum dot operation by positioning the strained Ge channel 55 nm below the semiconductor/dielectric interface. While this shallow heterostructure showed an ultra-high maximum mobility exceeding 5×105 cm2/Vs, possibly due to passivation of surface impurities by tunneled carriers from the QW, a rather high percolation density pp = 1.2 × 1011 cm−2 was measured.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
