Photegra Corporation

Emeryville, CA, United States

Photegra Corporation

Emeryville, CA, United States
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Jeong H.-S.,University of Suwon | Keller K.,Photegra Corporation | Culkin B.,Photegra Corporation
Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics | Year: 2017

Nonvacuum process technology was used to produce Cs3Sb photocathodes on substrates, and in situ panel devices were fabricated. The performance of the devices was characterized by measuring anode current as functions of the devices' operation times. An excitation light source with 475 nm wavelength was used for the photocathodes. The device has a simple diode structure, providing unique characteristics such as a large gap, vertical electron beam directionality, and resistance to surface contamination from ion bombardment and poisoning by outgassing species. Accordingly, Cs3Sb photocathodes function as flat emitters, and the emission properties of the photocathode emitters depend on the vacuum level of the devices. Improvement of current stability has been observed after conducting the electrical conditioning process to remove possible adsorbates on Cs3Sb flat emitters. © 2017 American Vacuum Society.


Jeong H.-S.,University of Suwon | Keller K.,Photegra Corporation | Culkin B.,Photegra Corporation
Journal of the Korean Physical Society | Year: 2017

Non-vacuum process technology was used to produce Cs3Sb photocathodes on substrates, and in-situ panel devices were fabricated. The performance of the devices was characterized by measuring the anode current as functions of the devices’ operation times. An excitation light source with a 475-nm wavelength was used for the photocathodes. The device has a simple diode structure, providing unique characteristics such as a large gap, vertical electron beam directionality, and resistance to surface contamination from ion bombardment and poisoning by outgassing species. Accordingly, Cs3Sb photocathodes function as flat emitters, and the emission properties of the photocathode emitters depend on the vacuum level of the devices. An improved current stability has been observed after conducting an electrical conditioning process to remove possible adsorbates on the Cs3Sb flat emitters. © 2017, The Korean Physical Society.


Jeong H.-S.,University of Suwon | Keller K.,Photegra Corporation | Culkin B.,Photegra Corporation
Journal of Vacuum Science and Technology B:Nanotechnology and Microelectronics | Year: 2015

A Cs3Sb photocathode was deposited on a flat metal surface using a nonvacuum processing technique and in-situ panel devices were fabricated. The technique does not require ultrahigh vacuum conditions as in conventional techniques. The electrical characteristics of the panel devices were investigated by measuring the anode current as functions of devices operation times. Blue light with a 450nm wavelength was used as an excitation source. The result shows that the Cs3Sb photocathode emitter has the potential of a long lifetime with stable electron emission characteristics in the panel making it a suitable cathode material for panel devices. © 2015 American Vacuum Society.


Jeong H.-S.,University of Suwon | Keller K.,Photegra Corporation | Culkin B.,Photegra Corporation
Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics | Year: 2015

This paper presents a new concept for a planar light source utilizing Cs3Sb photocathodes as flat electron emitters. The design concept of the devices with a diode structure was that the photocathodes were to be operated in a reflective mode. Commercially available P-22 phosphors were used as a light source of desirable wavelengths. Light emission from the devices was induced by photoemitted electrons, accelerated by an anode electric field that was shielded from the photoemitter surface. The luminescent characteristics of the devices were investigated by measuring the optical parameters as functions of applied anode voltages. The results showed the possibility to produce a more directable and easily controllable stream of light. These make the devices suitable for a variety of planar lighting applications. © 2015 American Vacuum Society.

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