Investigation of optically generated kink effect in GaAs-based heterojunction phototransistors

Abstract

An optically generated kink observed in the Gummel plot of AlGaAs/GaAs single heterojunction phototransistors (sHPTs) is reported when illuminated with relatively high optical powers. The observed sudden rise in collector current and decrease in the base current, referred to as 'optical kink effect', is carefully studied and analyzed. The measurements are performed for incident optical power of up to 225 µW at an incident wavelength of 635 nm. This rise in the current gain of HPTs, in three terminal configuration, is associated with the base-collector space-charge modulation similar to the kirk effect.