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Advanced Detectors, Systems, & Nanoscience

Stable Solar-Blind Ultraviolet Photocathodes without Cesiation

We are developing solar-blind photocathodes for ultraviolet detector applications, using intrinsically solar-blind gallium-nitride-based materials. Photocathodes absorb incoming light and emit photo-excited electrons from the device surface. When paired with microchannel plates or electron bombarded CCDs, they enable solar-blind UV imaging and photon counting detection.

While conventional photocathodes must be protected from air exposure in sealed vacuum tubes, we are developing air-exposable devices that will dramatically increase versatility and decrease cost. We use epitaxial techniques to exploit the natural high polarization and piezoelectricity of the gallium nitride semiconductor family in order to cause changes in the band structure and allow activation of these photocathodes.

Above: The response of a prototype device starts at the band gap of gallium nitride
 

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