Cameron Kopas

Cameron Kopas
Arizona State University | ASU · Department of Materials Science and Engineering

Materials Science

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17
Publications
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50
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Introduction

Publications

Publications (17)
Preprint
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The fundamental challenge underlying superconducting quantum computing is to characterize heterogeneity and disorder in the underlying quantum circuits. These nonuniform distributions often lead to local electric field concentration, charge scattering, dissipation and ultimately decoherence. It is particularly challenging to probe deep sub-waveleng...
Article
In this study, we show that deposited Ge and Si dielectric thin-films can exhibit low microwave losses at single-photon powers and sub-Kelvin temperatures (≈40 mK). This low loss enables their use in a wide range of devices, including coplanar, microstrip, and stripline resonators, as well as layers for device isolation, interwiring dielectrics, an...
Preprint
Full-text available
Superconducting qubits have emerged as a potentially foundational platform technology for addressing complex computational problems deemed intractable with classical computing. Despite recent advances enabling multiqubit designs that exhibit coherence lifetimes on the order of hundreds of $\mu$s, material quality and interfacial structures continue...
Article
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A distinct class of 2D layered quantum materials with the chemical formula of RTe3 (R = lanthanide) has gained significant attention owing to the occurrence of collective quantum states, superconductivity, charge density waves (CDW), spin density waves, and other advanced quantum properties. To study the Fermi surface nesting driven CDW formation,...
Preprint
Full-text available
Germanium thin films are an excellent candidate for use as a low-loss dielectric in superconducting microwave resonators, a low-loss inter-layer metal wiring dielectric, and passivation layers in microwave and Josephson junction devices. In Ge/Nb structures deposited at 400 {\deg}C, we observe intermixing over as much as 20 nm. The addition of a 10...
Article
This work reports on a comprehensive examination of the electrical and thermal properties of vertical Schottky diodes fabricated on ( 2 ¯ 01 )- and (001)-oriented samples of β-Ga2O3. The temperature-dependent current–voltage (I–V) and capacitance–voltage (C–V) data were gathered and analyzed down to 60 K. Deep level transient spectroscopy (DLTS) wa...
Preprint
Full-text available
Our study shows that deposited Ge and Si dielectric thin-films can exhibit low microwave losses at near single-photon powers and sub-Kelvin temperatures ($\approx$40 mK). This low loss enables their use in a wide range of devices, including low-loss coplanar, microstrip, and stripline resonators, as well as layers for device isolation, inter-wiring...
Preprint
The nature and concentration of defects near niobium-silicon interfaces prepared with different silicon surface treatments were characterized using current-voltage (I-V), deep level transient spectroscopy (DLTS), and secondary ion mass spectroscopy (SIMS). All samples have H, C, O, F, and Cl chemical contamination in the Si within 50 nm of the inte...
Article
We demonstrate a high-pressure soft sputtering technique that can grow large area 1T′ phase MoTe2 sheets on HOPG and Al2O3 substrates at temperatures as low as 300 °C. The results show that a single Mo/Te co-sputtering step on heated substrates produces highly defected films as a result of the low Te sticking coefficient. The stoichiometry is signi...
Article
A series of pyrite thin films were deposited in-situ in a monolayer-by-monolayer fashion using sequential evaporation of iron under high vacuum, followed by sulfidation at a sulfur pressure of 133 Pa, as a function of substrate temperature. The stoichiometry, crystallinity, topographic smoothness, and phase purity of the deposited pyrite thin films...
Article
Full-text available
This paper investigates the properties of thin films of chromium-doped Ni80Fe20 (Permalloy) that could potentially be useful in future low-power magnetic memory technologies. The addition of chromium reduces the saturation magnetization, Ms, which is useful for low-energy switching, but does not significantly degrade the excellent switching propert...
Article
Full-text available
The physical nature and concentration of paramagnetic point defects in the dielectrics of superconducting planar microwave resonators have been determined using in-situ electron paramagnetic resonance spectroscopy. To perform this work, the quality factor of parallel plate and stripline resonators was measured as a function of the magnitude of a ma...
Article
We have synthesized stoichiometric Ba(Cd1/3Ta2/3)O3 [BCT] (100) dielectric thin films on MgO (100) substrates using Pulsed Laser Deposition. Over 99% of the BCT film was found to be epitaxial [BCT (100) || MgO (100) and BCT (010) || MgO (010)] when grown with an elevated substrate temperature of 635 °C, an enhanced oxygen pressure of 53 Pa and a Cd...
Article
To understand the thermochemistry and determine the rate limiting steps of ZnGeAs2 thin-film synthesis, experiments were performed to measure the (a) thermal decomposition rate and (b) elemental composition and deposition rate of films produced with pulsed laser deposition (PLD). The decomposition rate is kinetically limited with an activation ener...

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