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Roberts, Dennice

Publications and source records attributed to Roberts, Dennice.

Metal Chalcogenides for Neuromorphic Computing: Emerging Materials and Mechanisms

The approaching end of Moore's Law scaling has significantly accelerated multiple fields of research including neuromorphic-, quantum-, and photonic computing, each of which possesses unique benefits unobtained through conventional binary computers. One of the most compelling arguments for neuromorphic computing systems is power consumption, noting that computations made in the human brain are approximately 106 times more efficient than conventional CMOS logic. This review article focuses on the materials science and physical mechanisms found in metal chalcogenides that are currently being explored for use in neuromorphic applications. We begin by reviewing the key biological signal generation and transduction mechanisms within neuronal components of mammalian brains and subsequently compare with observed experimental measurements in chalcogenides. With robustness and energy efficiency in mind, we will focus on short-range mechanisms such as structural phase changes and correlated electron systems that can be driven by low-energy stimuli, such as temperature or electric field. We aim to highlight fundamental materials research and existing gaps that need to be overcome to enable further integration or advancement of metal chalcogenides for neuromorphic systems.

36 MATERIALS SCIENCE↗

Dynamic Hydride Vapor Phase Epitaxy of III-V Materials for Photovoltaics Applications: Preprint

We demonstrate the uniqueness of Dynamic Hydride Vapor Phase Epitaxy (D-HVPE) to deposit III-V materials for high efficiency and potentially low-cost photovoltaics applications. Unlike traditional HVPE, D-HVPE allows for the deposition of relatively complex heterostructures and devices at high growth rates. We recently achieved record growth rates > 500 µm/h for GaAs and >200 µm/h for GaInP in our D-HVPE, and have not yet reached a growth rate limit for either material. We grew single junction GaAs solar cells at growth rates up to 309 µm/h without significant degradation of solar cell performance. We also demonstrate growth of Al-containing III-V materials in HVPE, a capability that makes D-HVPE more attractive for applications beyond photovoltaics.

D-HVPE↗