Functional wide band-gap semiconductors

New developments in functional wide-bandgap semiconductors.

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Prior research involved various wide-bandgap semiconductors including boron-doped diamond, SiC, SrTiO3 (STO) and most recently β-Ga2O3. The term functional refers to broad class of functionalities induced by quantum defects and interfaces and enabling potential applications in memory storage, scalable quantum computing, ultrafast power switching and other types of smart applications. For example, our recent STM study of β-Ga2O3 revealed (PRB, 2018) surface self-trapped holes supplied by tunneling transport from the STM tip and forming either glassy or ordered Wigner-crystal type structures on surfaces, and the ability to erase and to repopulate these self-trapped charge layers using STM voltage pulses.

Using wide-bandgap semiconductors for quantum information science historically started from the studies of NV-centers in diamond. Currently, of our interest for potential quantum computing applications are wide-bandgap semiconductors doped by rare-earth atoms (like Er3+) known for their exceptionally low dephasing rates. This development is in progress and we are currently working on growth methods of Er-doped STO samples.

Literature

I. Altfeder et al., Scanning tunneling microscopy of an interfacial two-dimensional electron gas in oxide heterostructures.

I. Altfeder, E. Bianco, D. Dorsey, Self-trapping and ordering of heavy holes in the wide band-gap semiconductor β−Ga2O3.

Z. Potůček et al., Optical spectroscopy of erbium-doped SrTiO3 crystals.