A theoretical and experimental evaluation of III–nitride solar-blind UV photocathode

We have developed a superior solar-blind ultraviolet (UV) photocathode with an Al${}_x$Ga${}_{1-x}$N photocathode ($x\sim 0.45$) in semi-transparent mode, and assessed spectra radiant sensitivity related to practical use. Before being grown over a basal plane sapphire substrate by low-pressure metal organic chemical vapor deposition (MOCVD), a reasonable design was made to the photocathode epitaxy structure, focusing on the Al${}_x$Ga${}_{1-x}$N: Mg active layer, then followed by a comprehensive analysis of the structural and optical characterization. The spectra radiant sensitivity is peaked of 41.395 mA/W at wavelength 257 nm and then decreases by about 3 to 4 decades at 400 nm demonstrating the ability of this photocathode for solar-blind application prospects. (paper)