Electric field variation of photoconductivity quenching due to hot electron capture in ZnIn2S4

Abstract

The study of the photoconductivity quenching as a function of the electric field in the ternary compound ZnIn2S4 has given evidence of a level localized at about 1.77 eV above the valence band which is responsible for the capture of hot electrons and for the N-type negative resistance. By a rough estimate of the quenching compared with the experimental it was possible to determine the potential barrier offered by the centre to the electrons, for a fixed illumination intensity of the gap energy light upon the crystal. L'etude du quenching de la photoconducibilite en fonction du champ electrique en monocristaux de ZnIn2S4 nous a donne la possibilite de trouver un niveau localise au voisinage de 1,77 eV au-dessus du sommet de la bande de valence qui est responsable pour la capture des electrons chauds et ainsi de la resistance negative type N. Un'estimation approximee du quenching comparee avec les resultats experimentaux a donne la possibilite de determiner la barriere de potentiel que le niveau presente aux electrons, pour une intensite donnee de lumiere de frequence correspondente a l'energie de la bande interdite.