Effect of illumination on electrical parameters of Au/(P3DMTFT)/ n -GaAs Schottky barrier diodes

Reverse- and forward-bias current–voltage ( I – V ) data of the Au/(P3DMTFT)/ n -GaAs Schottky barrier diodes (SBDs) were measured in dark and at under various illumination levels (from 50 to 200 W with steps of 25 W) for the purpose of examining the change in electrical parameters such as zero-bias barrier height ( Φ bo ), ideality factor ( n ), reverse saturation current ( I o ), series resistance ( R s ) and shunt resistance ( R sh ) with illumination. The values of n , Φ bo and I o were determined using I – V data in dark as 1.34, 0.91 eV and 7.25 × 10 −12 A, respectively. On the other hand, these parameters were obtained as 1.85, 0.80 eV and 5.11 × 10 −10 A, respectively, when the SBD is exposed to 200 W illumination. The values of shunt resistance ( R sh ) and series resistance ( R s ) were determined from Ohm’s law and shown as R i –V plots. Additionally, Cheung’s and modified Norde’s functions were also utilized for the extraction of R s in dark and under various illumination levels. The energy density distribution profiles of interface states ( N ss ) were investigated for various illumination levels. The dependency of the energy density distribution profiles of interface states ( N ss ) on illumination levels was investigated. Obtained results suggest that these electrical parameters are sensitive to illumination. Moreover, Au/(P3DMTFT)/ n -GaAs SBDs shows remarkable photovoltaic performance with the values of short-circuit current ( I sc ) of 1.45 × 10 −6 A, open-circuit voltage ( V oc ) of 0.37 V and fill factor of 0.65 under 200 W illumination.