Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno

Technische Universiteit Delft

Pieter Thijs Eendebak

Jasper Winters

Lieven Mark Koenraad Vandersypen

Wietse Van Dijk

Timothy Alexander Baart

Nodar Samkharadze

Tim Bosch

Wouter Oosterheert

Gu Johanna Willemina Van Rhijn

Semiconductor element, method of reading out a quantum dot device and system. The present document relates to a semiconductor element for providing a source reservoir for a charge sensor of a quantum dot device. The element comprises a semiconductor heterostructure () including a quantum well layer () contiguous to a semiconductor functional layer (), one or more ohmic contacts () for providing charge carriers, and a first accumulation gate electrode () located opposite the quantum well layer and spaced apart therefrom at least by the semiconductor functional layer for enabling to form a two dimensional charge carrier gas () in a first area of the quantum well layer upon applying a first biasing voltage to the first accumulation gate electrode. The device further comprises a second accumulation gate electrode () opposite the quantum well layer and electrically isolated from the first accumulation gate electrode (), the second accumulation gate electrode enabling to be biased with a second biasing voltage, for enabling to extend the two dimensional charge carrier gas in a second area () contiguous to the first area. This document further relates to a method of determining a spin state in a quantum dot device, as well as a system comprising a quantum dot device and a semiconductor element.

Semiconductor element, method of reading out a quantum dot device and system

Quantum dot circuit and a method of characterizing such a circuit Voltages that enable control of electron occupation in a series of quantum dots are determined by a method of measuring effects of gate electrode voltages on a quantum dot circuit. The quantum dot circuit comprises a channel (), first gate electrodes (-) that extend over locations along the edge of the channel to create potentials barriers defining the potentials well therebetween, as well as second gate electrodes (-) adjacent to potential wells, for controlling depths of the successive electrical potential wells between the potential barriers. First, channel currents are measured in a pre-scan of bias voltages of the first gates for controlling the potential barriers. The result is used to set their bias levels in, a scan over a two-dimensional range of combinations of bias voltages on the second gates for controlling the depths. In this scan an indication of charge carrier occupation of potential wells at consecutive positions along the channel such as electromagnetic wave reflection is measured. Pattern matching with a pattern of crossing occupation edges is applied to the result. This involves a two-dimensional image that has the combinations of the bias voltages as image points and the indication of charge carrier occupation as image values. The pattern matching detects an image point where the image matches a pattern of crossing edges along predetermined directions.

Quantum dot circuit and a method of characterizing such a circuit

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Utrecht, Netherlands

Pieter Thijs Eendebak