Fabrication And Photoemission Theory Simulation Of GaAs Nanowire Arrays Photocathode

With the advantages of high quantμm efficiency, low dark current, good long-wavelength response and narrow energy spread, Negative-electron-affinity(NEA) GaAs photocathodes have shown widespread applications including the weak light detection, high energy physics, photomultiplier tubes, and are becoming more potential sources for the next-generation electron accelerators. In the past few years, GaAs photocathodes structure optimization design and theory research based on bulk GaAs material, nanowire arrays structure characterization have made great achievements, but the study on the negative-electron-affinity GaAs nanowire arrays photocathode is still not been reported. In this work, we performed some thorough studies on GaAs arrays fabrication and optimization, characterization techniques test, theory model simulation.In this paper, inductively coupled plasma(ICP) etching was used to fabricate the GaAs/AlGaAs nanowire arrays, anlaysis the factors affecting the top stripping of GaAs nanowire arrays fabricated by ICP etching and optimizate the fabrication process. Using scanning electron microscope(SEM), photoluminesecence spectroscopy(PL), reflectance spectroscopy to investigate the optical properties of GaAs nanowire arrays. Compared with bulk material, the reflectance ratio of GaAs nanowire arrays is apparently lower due to the intrinsic antireflection effect(which increases light absorption).Based on experiments, aiming at its characterization test, introducing theoretical analysis and mathematics modeling, the simulation was used to investigate the affect of incident angle, incident wavelength, nanowire size to the GaAs nanowire arrays photocathode. The simulation results indicated that with the increase of the incident angle, GaAs nanowire arrays spectral response is not only first increased and then decreased, which is extremely different with bulk structure, but also higher than bulk structure.