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  1. Abstract

    Nitrogen-vacancy (NV) and silicon-vacancy (SiV) color defects in diamond are promising systems for applications in quantum technology. The NV and SiV centers have multiple charge states, and their charge states have different electronic, optical and spin properties. For the NV centers, most investigations for quantum sensing applications are targeted on the negatively charged NV (NV), and it is important for the NV centers to be in the NVstate. However, it is known that the NV centers are converted to the neutrally charged state (NV0) under laser excitation. An energetically favorable charge state for the NV and SiV centers depends on their local environments. It is essential to understand and control the charge state dynamics for their quantum applications. In this work, we discuss the charge state dynamics of NV and SiV centers under high-voltage nanosecond pulse discharges. The NV and SiV centers coexist in the diamond crystal. The high-voltage pulses enable manipulating the charge states efficiently. These voltage-induced changes in charge states are probed by their photoluminescence spectral analysis. The analysis result from the present experiment shows that the high-voltage nanosecond pulses cause shifts of the chemical potential and can convert the charge states of NV and SiV centers with the transition rates of ∼MHz. This result also indicates that the major population of the SiV centers in the sample is the doubly negatively charged state (SiV2−), which is often overlooked because of its non-fluorescent and non-magnetic nature. This demonstration paves a path for a method of rapid manipulation of the NV and SiV charge states in the future.

     
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  2. This study evaluates the beneficial effects of discharging nanosecond pulse transient plasma (NPTP) in a coaxial electrostatic precipitator for capturing nanoscale soot particles (∼50 nm) produced by an ethylene flame. 
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    Free, publicly-accessible full text available October 30, 2024
  3. Free, publicly-accessible full text available July 27, 2024
  4. Abstract

    In this work, a low temperature templated liquid phase (LT‐TLP) growth process is presented, that enables one to directly grow high optoelectronic quality single crystalline compound semiconductors (InP and InAs) on amorphous dielectrics at temperatures below 400 °C. Uniquely, the material quality is optimal when InP is grown at 300 °C, a temperature which is low enough to enable back‐end‐of‐line growth on fully fabricated Si complementary metal oxide semiconductor circuits. Using this low‐temperature grown InP, a transistor fabrication process is then entirely carried out at 300 °C or below, and an indium phosphide nanoribbon field effect transistor with excellent on/off ratios is demonstrated, indicating low defect density in the material. Overall, this approach enables growth of large area (tens of micron) single crystal compound semiconductor at low temperatures, establishing a back‐end‐of‐line (BEOL) compatible process for monolithic 3D device integration.

     
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