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...

Active refrigeration of optoelectronic components through the use of thin film solid state coolers based on III-V materials is proposed and investigated. Enhanced cooling power comparing to the thermoelectric effect of the bulk material is achieved through thermionic emission of hot electrons over a heterostructure barrier layer. It is shown that these heterostructures can be monolithically int...

A theory for the single-channel hollow cathode (SCHC) that includes the relevant physical processes and predicts the operating parameters is presented. A SCHC consists of a cylindrical channel approximately ten diameters in length through which a working gas (taken as lithium vapor here) flows and exits as a plasma. A high current (1-100 A) is conducted into the channel by the plasma and to the...

Since the discovery of X-rays over a century ago the techniques applied to the engineering of X-ray sources have remained relatively unchanged. From the inception of thermionic electron sources, which, due to simplicity of fabrication, remain central to almost all X-ray applications, there have been few fundamental technological advances. However, with the emergence of ever more demanding medic...