Thickness dependent trap states and mobility in 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole

Abstract

Electron transport in 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole is investigated as a function of temperature and organic layer thickness. Conduction mechanism has been found to be affected by trap states. The current density-voltage characteristics have been found to follow the trap charge limited conduction model. The density of trap states and trap energy has been found to be dependent on sample thickness. As the thickness has increased from 100 nm to 150 nm, trap energy has correspondingly increased from 80 meV to 135 meV and density of trap states has been found to decrease from 1.6 × 1018 to 3.5 × 1017 per cm3. Mobility has been found to be increasing with the decrease in thickness.