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Vink, I.T. (author), Nooitgedagt, T. (author), Schouten, R.N. (author), Vandersypen, L.M.K. (author), Wegscheider, W. (author)The authors employ a cryogenic high electron mobility transistor (HEMT) amplifier to increase the bandwidth of a charge detection setup with a quantum point contact (QPC) charge sensor. The HEMT is operating at 1?K and the circuit has a bandwidth of 1?MHz. The noise contribution of the HEMT at high frequencies is only a few times higher than...journal article 2007
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Bodoky, F. (author), Belzig, W. (author), Bruder, C. (author)We investigate the current and noise characteristics of a double quantum dot system. The strong correlations induced by the Coulomb interaction and the Pauli principle create entangled two-electron states and lead to signatures in the transport properties. We show that the interaction parameter Ø, which measures the admixture of the double...journal article
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Lodari, M. (author), Hendrickx, N.W. (author), Lawrie, W.I.L. (author), Hsiao, T. (author), Vandersypen, L.M.K. (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author)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 × 10 10 cm−2 , indicative of a very...journal article 2021
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Gudjónsdóttir, S. (author), Houtepen, A.J. (author)Arguably the most controllable way to control the charge density in various semiconductors, is by electrochemical doping. However, electrochemically injected charges usually disappear within minutes to hours, which is why this technique is not yet used to make semiconductor devices. In this manuscript, electrochemical doping of different...journal article 2020
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Vonk, Sander J.W. (author), Heemskerk, Bart A.J. (author), Keitel, Robert C. (author), Hinterding, Stijn O.M. (author), Geuchies, J.J. (author), Houtepen, A.J. (author), Rabouw, Freddy T. (author)Broadening of multiexciton emission from colloidal quantum dots (QDs) at room temperature is important for their use in high-power applications, but an in-depth characterization has not been possible until now. We present and apply a novel spectroscopic method to quantify the biexciton line width and biexciton binding energy of single CdSe...journal article 2021
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Xia, Fei (author), Gevers, Monique (author), Fognini, Andreas (author), Mok, Aaron T. (author), Li, Bo (author), Akbari, Najva (author), Esmaeil Zadeh, I.Z. (author), Qin-Dregely, Y. (author), Xu, Chris (author)Optical microscopy is a valuable tool for in vivo monitoring of biological structures and functions because of its noninvasiveness. However, imaging deep into biological tissues is challenging due to the scattering and absorption of light. Previous research has shown that the two optimal wavelength windows for high-resolution deep mouse brain...journal article 2021
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Vogel, Y.B. (author), Stam, M. (author), Mulder, J.T. (author), Houtepen, A.J. (author)We present a strategy to actively engineer long-range charge transport in colloidal quantum dot assemblies by using ligand functionalities that introduce electronic states and provide a path for carrier transfer. This is a shift away from the use of inactive spacers to modulate charge transport through the lowering of the tunneling barrier...journal article 2022
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Llusar, Jordi (author), du Fossé, I. (author), Hens, Zeger (author), Houtepen, A.J. (author), Infante, Ivan (author)Although density functional theory (DFT) calculations have been crucial in our understanding of colloidal quantum dots (QDs), simulations are commonly carried out on QD models that are significantly smaller than those generally found experimentally. While smaller models allow for efficient study of local surface configurations, increasing the...journal article 2023
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Mangnus, Mark J.J. (author), de Wit, Jur W. (author), Vonk, Sander J.W. (author), Geuchies, J.J. (author), Albrecht, Wiebke (author), Bals, Sara (author), Houtepen, A.J. (author), Rabouw, Freddy T. (author)In recent years, quantum dots (QDs) have emerged as bright, color-tunable light sources for various applications such as light-emitting devices, lasing, and bioimaging. One important next step to advance their applicability is to reduce particle-to-particle variations of the emission properties as well as fluctuations of a single QD’s...journal article 2023
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Ungerer, J. H. (author), Chevalier Kwon, P. (author), Patlatiuk, T. (author), Ridderbos, J. (author), Kononov, A. (author), Sarmah, D. (author), Bakkers, E.P.A.M. (author), Zumbühl, D. (author), Schönenberger, C. (author)Spin qubits in germanium are a promising contender for scalable quantum computers. Reading out of the spin and charge configuration of quantum dots formed in Ge/Si core/shell nanowires is typically performed by measuring the current through the nanowire. Here, we demonstrate a more versatile approach on investigating the charge configuration...journal article 2023
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Almeida, Guilherme (author), van der Poll, L.M. (author), Evers, W.H. (author), Szoboszlai, Emma (author), Vonk, Sander J.W. (author), Rabouw, Freddy T. (author), Houtepen, A.J. (author)Indium phosphide colloidal quantum dots (CQDs) are the main alternative for toxic and restricted Cd based CQDs for lighting and display applications. Here we systematically report on the size-dependent optical absorption, ensemble, and single particle photoluminescence (PL) and biexciton lifetimes of core-only InP CQDs. This systematic study...journal article 2023
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Pietra, F. (author), De Trizio, L. (author), Hoekstra, Anne W. (author), Renaud, N. (author), Prato, Mirko (author), Grozema, F.C. (author), Baesjou, Patrick J. (author), Koole, Rolf (author), Manna, L. (author), Houtepen, A.J. (author)Colloidal quantum dots (QDs) show great promise as LED phosphors due to their tunable narrow-band emission and ability to produce high-quality white light. Currently, the most suitable QDs for lighting applications are based on cadmium, which presents a toxicity problem for consumer applications. The most promising cadmium-free candidate QDs...journal article 2016
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Stam, M. (author), du Fossé, I. (author), Infante, Ivan (author), Houtepen, A.J. (author)Quantum dots (QDs) are known for their size-dependent optical properties, narrow emission bands, and high photoluminescence quantum yield (PLQY), which make them interesting candidates for optoelectronic applications. In particular, InP QDs are receiving a lot of attention since they are less toxic than other QD materials and are hence...journal article 2023
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Marino, Emanuele (author), Kodger, Thomas E. (author), Crisp, R.W. (author), Timmerman, Dolf (author), MacArthur, Katherine E. (author), Heggen, Marc (author), Schall, Peter (author)Solar devices based on semiconductor nanoparticles require the use of conductive ligands; however, replacing the native, insulating ligands with conductive metal chalcogenide complexes introduces structural defects within the crystalline nanostructure that act as traps for charge carriers. We utilized atomically thin semiconductor...journal article 2017
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Mulder, J.T. (author), Kirkwood, N.R.M. (author), De Trizio, Luca (author), Li, Chen (author), Bals, Sara (author), Manna, L. (author), Houtepen, A.J. (author)Indium phosphide quantum dots (QDs) have drawn attention as alternatives to cadmium- and lead-based QDs that are currently used as phosphors in lamps and displays. The main drawbacks of InP QDs are, in general, a lower photoluminescence quantum yield (PLQY), a decreased color purity, and poor chemical stability. In this research, we attempted...journal article 2020
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Crisp, R.W. (author), Kirkwood, N.R.M. (author), Grimaldi, G. (author), Kinge, Sachin (author), Siebbeles, L.D.A. (author), Houtepen, A.J. (author)InP and InZnP colloidal quantum dots (QDs) are promising materials for application in light-emitting devices, transistors, photovoltaics, and photocatalytic cells. In addition to possessing an appropriate bandgap, high absorption coefficient, and high bulk carrier mobilities, the intrinsic toxicity of InP and InZnP is much lower than for...journal article 2018
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Spoor, F.C.M. (author), Grimaldi, G. (author), Kinge, Sachin (author), Houtepen, A.J. (author), Siebbeles, L.D.A. (author)Carrier multiplication (CM) is the process in which multiple electron–hole pairs are created upon absorption of a single photon in a semiconductor. CM by an initially hot charge carrier occurs in competition with cooling by phonon emission, with the respective rates determining the CM efficiency. Up until now, CM rates have only been calculated...journal article 2019
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Tunable Coupling and Isolation of Single Electrons in Silicon Metal-Oxide-Semiconductor Quantum DotsEenink, H.G.J. (author), Petit, L. (author), Lawrie, W.I.L. (author), Clarke, J. S. (author), Vandersypen, L.M.K. (author), Veldhorst, M. (author)Extremely long coherence times, excellent single-qubit gate fidelities, and two-qubit logic have been demonstrated with silicon metal-oxide-semiconductor spin qubits, making it one of the leading platforms for quantum information processing. Despite this, a long-standing challenge in this system has been the demonstration of tunable tunnel...journal article 2019
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Gudjónsdóttir, S. (author), van der Stam, W. (author), Koopman, Christel (author), Kwakkenbos, Bob (author), Evers, W.H. (author), Houtepen, A.J. (author)Semiconductor films that allow facile ion transport can be electronically doped via electrochemistry, where the amount of injected charge can be controlled by the potential applied. To apply electrochemical doping to the design of semiconductor devices, the injected charge has to be stabilized to avoid unintentional relaxation back to the...journal article 2019
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Crisp, R.W. (author), Hashemi, Fatemeh S.M. (author), Alkemade, J. (author), Kirkwood, N.R.M. (author), Grimaldi, G. (author), Kinge, S.S. (author), Siebbeles, L.D.A. (author), van Ommen, J.R. (author), Houtepen, A.J. (author)To improve the stability and carrier mobility of quantum dot (QD) optoelectronic devices, encapsulation or pore infilling processes are advantageous. Atomic layer deposition (ALD) is an ideal technique to infill and overcoat QD films, as it provides excellent control over film growth at the sub-nanometer scale and results in conformal...journal article 2020