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

Abstract

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 (Φbo), ideality factor (n), reverse saturation current (Io), series resistance (Rs) and shunt resistance (Rsh) with illumination. The values of n, Φbo and Io 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 (Rsh) and series resistance (Rs) were determined from Ohm’s law and shown as Ri–V plots. Additionally, Cheung’s and modified Norde’s functions were also utilized for the extraction of Rs in dark and under various illumination levels. The energy density distribution profiles of interface states (Nss) were investigated for various illumination levels. The dependency of the energy density distribution profiles of interface states (Nss) 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 (Isc) of 1.45 × 10−6 A, open-circuit voltage (Voc) of 0.37 V and fill factor of 0.65 under 200 W illumination.