Direct excitation of xenon by ballistic electrons emitted from nanocrystalline‐silicon planar cathode and vacuum‐ultraviolet light emission

Abstract

Abstract— To verify the possible use of energetic electrons for direct excitation of inert gas molecules, a nanocrystalline‐silicon (nc‐Si) planar ballistic emitter is operated in a high‐pressure xenon gas ambience. Under the pulse drive, vacuum‐ultraviolet (VUV) light emission is detected without any signs of discharge. The transient behavior of the VUV light emission properly corresponds to that of the nc‐Si emitter. In accordance with quantitative analyses of electron‐emission characteristics and the VUV output, the electron‐to‐photon conversion efficiency reaches 81% in the relatively efficient emitter case. The VUV output power is mainly determined from the number of electrons with energies compatible the with internal excitation of xenon. The emission spectrum observed at a pressure of 10 kPa shows peaks at 152 and 172 nm, which are thought to be originated from metastable Xe2* states. In contrast to the case of conventional impact ionization, no near‐infrared (NIR) peaks are seen in the spectrum. These results strongly suggest that the incidence of energetic electrons causes direct excitation of xenon molecules followed by radiative relaxation through intermediate states. The generated VUV light can be easily converted to visible light using a phosphor screen. As a discharge‐free VUV light emission, this phenomenon is potentially applicable to mercury‐free, high‐efficacy, and high‐stability flat‐panel light‐emitting device.

Improved electron emission properties of the porous silicon emitter by chemical surface modification

“…One of the most important devices based on the PS is the cold cathode electron emitter, which has significant advantages including a relatively simple structure, general processing, low operation voltage, ballistic emission, and insensitivity to gas pressure and gas species when emitting electrons [6]. Utilizing these advantages, applicability to vacuum-type flat panel displays [7], electron beam lithography [8],…”

Reductive Deposition of Thin Cu Films Using Ballistic Hot Electrons as a Printing Beam

“…In comparison with conventional cold cathodes, there are some advantageous features in this emitter: extremely high mean energies of as-emitted electrons (5-7 eV at an applied voltage of 15-20 V), 4 surface emissivity with a small angle dispersion (±10 • to the surface normal), 7 low sensitivity of emission to ambient pressure, and compatibility with planar process for device fabrication and with active-matrix drive. The usefulness of the nc-Si emitter has been demonstrated in vacuum (parallel electron beam (EB) lithography), 7 in atmospheric-pressure gases (VUV emission from Xe atoms), 8 and in aqueous solutions (H 2 generation). 9,10 When the nc-Si emitter is driven in metal salt solutions, ballistic hot electrons induces the reductive reaction leading to the deposition of thin metal films.…”