Comparative research on resolution characteristics between transmission-mode exponential-doping and uniform-doping GaAs photocathodes

摘要

Usingthemodulationtransferfunctionobtainedbyestablishingandsolvingthetwo-dimensionalcontinuityequation,wehavecalculatedandcomparativelyanalysedtheresolutioncharacteristicsoftransmission-modeexponential-dopinganduniform-dopingGaAsphotocathodes.Thecalculatedresultsshowthat,comparedwiththeuniform-dopingGaAsphotocathode,theexponential-dopingstructurecanupgradesignificantlynotonlytheresolutionbutalsothequantumefficiencyofanegativeelectronaffinityGaAsphotocathode.Thisimprovementdiffersfromthemethodforhighresolutionbyreducingtheemissionlayerandtheelectrondiffusionlengthnbsp;orbyincreasingtherecombinationvelocityofback-interface,whichleadstoalowquantumefficiency.Moreover,theimprovementofresolutionandquantumefficiencyfortransmission-modeexponential-dopingGaAsphotocathodeistheresultoffacilitatingtheelectrontransportandnbsp;restrainingthelateraldiffusionbythebuilt-inelectricfield.