Electrical power >1 mW is dissipated in semiconducting single-walled carbon nanotube devices in a vacuum. After high-power treatment, devices exhibit lower on currents and intrinsic, ambipolar behavior with near-ideal thermionic emission from Schottky barriers of height one-half the band gap. Upon exposure to air, devices recover p-type behavior, with positive threshold and ohmic contacts. The ...

Proof-of-concept experimental results stemming from beam simulations for a microfocus electron gun are presented. The simulations demonstrate the potential to produce 4 mA of current through a 40m-diameter spot, at an energy of 30 keV, emitted from a 1-mm-diameter cathode with low energy spread and high brightness. The experimental realization, scaled down for practicality, but consistent with ...

Photon-enhanced thermionic emission (PETE) converts sunlight to electricity with the combined photonic and thermal excitation of charge carriers in a semiconductor, leading to electron emission over a vacuum gap. Theoretical analyses predict conversion efficiency that can match, or even exceed, the efficiency of traditional solar thermal and photovoltaic converters. Several materials have been ...

Carbon nanotubes CNTs are promising candidates to create new thermionicand photoemission materials. Intercalation of CNTs with alkali metals, such as potassium, greatly reduces their work functions, and the low electron scattering rates of small-diameter CNTs offer the possibility of efficient photoemission. This work uses a Nd:YAG YAG denotes yttrium aluminum garnet laser to irradiate singlean...

The current-voltage (I-V) characteristics of Pt/(n.u.d)-GaN and Pt/Si-doped-GaN diodes Schottky are investigated. Based on these measurements, physical mechanisms responsible for electrical conduction have been suggested. The contribution of thermionic-emission current and various other current transport mechanisms were assumed when evaluating the Schottky barrier height. Thus the generation-re...