We successfully demonstrate for the first-time field emission (FE) from and to the two-dimensional electron gas (2DEG) formed in AlGaN/GaN heterojunction based lateral nanoscale vacuum emission diodes. In addition, we demonstrate FE with an AlGaN/GaN cathode and metallic anode. Our FE measurements demonstrate that these vacuum diodes with AlGaN/GaN and metallic anodes can deliver emission current in the range of microamps to milliamps, respectively, when biased within a range from 5 to 30 V.
In this work, we describe a testbed for studying free-electron photon interactions in a 1 to 20-keV scanning electron microscope. The setup includes an ultrafast emitter, optical modulators for structuring the electron beam, a nanostructured interaction zone, and electron and optical spectrometers with time-tagging electronics to characterize these interactions. Through this work we aim to understand these interactions at electron energies orders-of-magnitude lower than used in most previous work, enabling their more widespread adoption and potentially leading to chip-scale technologies.
We have developed a thermal radiation (blackbody emission) hyperspectroscopy apparatus with a spectral range of ~ 1–7 µm and a spatial resolution of ~10 µm, with the sample held in an ultra-high vacuum chamber. This system enables the detailed analysis of thermal photon emission from nanomaterials/structures and temperature mapping up to thermionic electron emission temperatures under high thermal gradients and with high spectral fidelity. It is thus a useful characterization tool for studying the role of low-dimensional physics in thermal transport and emission and related phenomena such as heat localization in nanotubes.
This study explores the potential of using a multi-beam system with carbon nanotubes (CNTs) as field emission X-ray sources for next-generation medical and industrial imaging and diagnosis techniques like tomosynthesis. CNTs' ability to withstand high temperatures and digital properties make them ideal for the multi-beam system. Using the multi-beam system with multiple CNT X-ray tubes can achieve faster image acquisition, reduced patient dose, and 3D reconstructed image. Overall, this study demonstrates the need and the advantages of using a multi-beam system with CNT-based X-ray sources for advanced imaging and therapy techniques.
The purpose of this study was to evaluate the effect of electrical aging on the cold cathode electron beam (C-beam). This experiment is performed by the vertically aligned carbon nanotube in which it is established that the applied bias for efficient electrical aging and defined the bias voltage as the voltage at which joule heating occurred. A long-term stable field electron emission from carbon nanotube arrays can be achieved through an aging process at high emission current. Additionally, x-ray imaging and dose measurement were used to assess the Focal Spot Size (FSS) of the tungsten cross wire used as a standard resolution testing object (EN 12543–5). We found that the aging had no significant effect on the FSS, but the x-ray dose rate enhanced from 0.45 mGy/sec to 1.1 mGy/sec.
