Ex situ hydrogen passivation effect of visible p-i-n type thin-film light-emitting diode characteristics

Abstract

The effect of ex situ hydrogen passivation process on the performance of visible hydrogenated amorphous silicon carbide ͑a-SiC:H͒-based p-i-n type thin-film light-emitting diodes has been investigated. An ex situ hydrogen passivation process dramatically improved the device performance; that is, the threshold voltage decreased by about 5 V, the electroluminescence ͑EL͒ intensity increased by a factor of about 3, and the EL peak shifted toward a short wavelength from 700 to 600 nm, resulting in an increase of the brightness from 1 cd/m 2 to 35 cd/m 2 . This improvement of device performance is caused by the passivation of interface states in the p/i and i/n interfaces as well as midgap states in the luminescent active intrinsic a-SiC:H layer by hydrogen atoms. A process time dependence of the ex situ hydrogen passivation effect on the device performance also has been studied.