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Valley splitting of single-electron Si MOS quantum dots

Applied Physics Letters

Gamble, John K.; Harvey-Collard, Patrick; Jacobson, Noah T.; Baczewski, Andrew D.; Nielsen, Erik N.; Maurer, Leon; Montano, Ines M.; Rudolph, Martin R.; Carroll, Malcolm; Yang, C.H.; Rossi, A.; Dzurak, A.S.; Muller, Richard P.

Silicon-based metal-oxide-semiconductor quantum dots are prominent candidates for high-fidelity, manufacturable qubits. Due to silicon's band structure, additional low-energy states persist in these devices, presenting both challenges and opportunities. Although the physics governing these valley states has been the subject of intense study, quantitative agreement between experiment and theory remains elusive. Here, we present data from an experiment probing the valley states of quantum dot devices and develop a theory that is in quantitative agreement with both this and a recently reported experiment. Through sampling millions of realistic cases of interface roughness, our method provides evidence that the valley physics between the two samples is essentially the same.

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TYPE Journal Article YEAR 2016
ScopusOSTIDOI

Selective layer disordering in intersubband Al0.028Ga0.972 N/AlN superlattices with silicon nitride capping layer

Applied Physics Express

Wierer Jr, Jonathan W.; Allerman, A.A.; Skogen, Erik J.; Tauke-Pedretti, Anna; Vawter, Gregory A.; Montano, Ines M.

We demonstrate the selective layer disordering in intersubband Al0.028Ga0.972 N/AlN superlattices using a silicon nitride (SiNx) capping layer. The (SiNx) capped superlattice exhibits suppressed layer disordering under high-temperature annealing. In addition, the rate of layer disordering is reduced with increased SiNx thickness. The layer disordering is caused by Si diffusion, and the SiNx layer inhibits vacancy formation at the crystal surface and ultimately, the movement of Al and Ga atoms across the heterointerfaces. In conclusion, patterning of the SiNx layer results in selective layer disordering, an attractive method to integrate active and passive III–nitride-based intersubband devices.

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TYPE Journal Article YEAR 2015
OSTIDOI

Layer disordering and doping compensation of an intersubband AlGaN/AlN superlattice by silicon implantation

Applied Physics Letters

Wierer, J.J.; Allerman, A.A.; Skogen, Erik J.; Tauke-Pedretti, Anna; Alford, Charles A.; Vawter, Gregory A.; Montano, Ines M.

Layer disordering and doping compensation of an Al0.028Ga0.972N/AlN superlattice by implantation are demonstrated. The as-grown sample exhibits intersubband absorption at ∼1.56 μm which is modified when subject to a silicon implantation. After implantation, the intersubband absorption decreases and shifts to longer wavelengths. Also, with increasing implant dose, the intersubband absorption decreases. It is shown that both layer disordering of the heterointerfaces and doping compensation from the vacancies produced during the implantation cause the changes in the intersubband absorption. Such a method is useful for removing absorption in spatially defined areas of III-nitride optoelectronic devices by, for example, creating low-loss optical waveguides monolithically that can be integrated with as-grown areas operating as electro-absorption intersubband modulators.

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TYPE Journal Article YEAR 2014
ScopusOSTIDOI

Summary of NEMO3D Calculations on RedSky

Muller, Richard P.; Montano, Ines M.

We have been using RedSky to investigate the physics of donor atoms in silicon for use as qubits for quantum computing. Quantum computing promises to dramatically change the performance of certain algorithms; this work is part of a quantum computing project led by Malcolm Carroll. We have investigated the magnitude of energy barriers for transferring electrons between donor centers and to elecrostaticallydefined quantum dots at the silicon oxide interface. Understanding these barriers helps us design structures that we think will be robust to noise and decoherence effects, and will help us understand experimental results as we build preliminary structures. There are only a few other research groups in the world conducting research along these lines. The work has been an important element of understanding the design principles that constrain computing devices at low temperature. We will continue this work in the future, in particular to analyze experimental results we anticipate coming from CINT collaborators.

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TYPE Other Report YEAR 2014
OSTIDOI
Results 1–25 of 45
Results 1–25 of 45