  We report on the growth and characterization of a new class of photocathode
structures for application as electron sources to produce high brightness
electron beams for accelerator applications. The sources are realized using
III-Nitride materials and are designed to leverage the strong polarization
field characteristic of this class material while grown in their wurtzite
crystal structure to produce a negative electron affinity condition without the
use of Cs, possibly allowing these materials to be operated in RF gun. A
Quantum Efficiency (QE) of about 1x10$^{-3}$ and a Mean Transverse Energy (MTE)
of electron of about 100 meV are measured at the operating wavelength of 265
nm. In a vacuum level of 3x10$^{-10}$ Torr the QE does not decrease after more
than 24 hours of continuous operation. The lowest MTE, about 50 meV, is
measured at 300 nm where the measured QE is 1.5x10$^{-5}$. Surface
characterizations reveal possible contribution to the MTE due to the surface
morphology calling for more detailed studies.
