Photoelectron Extraction Efficiency of N,N′-Bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD) in CH4 and Ar+ CH4 Mixtures

Abstract

Photoelectron extraction efficiency of N,N′-Bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD) was measured in pure Methane (CH4) and in mixtures of Methane (CH4) & Argon (Ar) with different ratios at 200 Torr pressure as a function of applied reduced electric field. In pure methane the quantum efficiency (QE) reaches to maximum value of ~97% of vacuum value in charge collection mode approximately at reduced field of 4 Vcm.-1Torr. In Ar+CH4, the QE reaches to ~95%, 94% and 95% with 50:50, 80:20 and 90:10 ratios respectively, in charge multiplication mode at lower reduced electric field values i.e. 3.5 Vcm-1.Torr, 2.5 Vcm-1.Torr and 2 Vcm-1.Torr respectively at 190 nm.