Structure and electrical resistance of the passivating ZnSe layer on Ge

Abstract

In this article, we have considered the p-i-n Ge photodetector with ZnSe passivating layer. Passivation layer needs to be protected photodetector from dust, rain drops and other external influences. However, this passivation layer can cause errors in photodetector image. When creating a passivating ZnSe layer on Ge, which is used in p-i-n Ge photodetectors, we found two additional phases GeSe and GeSe2 that do not contradict with their state diagram. The above phases can have an essential effect on performances of the passivating layer. Therefore, to study the electrical resistance of this layer, we prepared model samples of layers containing the GeSe and GeSe2 with the thickness 0.5…1.8 µm and area 1 cm2. To measure the electrical resistance of these layers, we used elastic contacts. The performed measurements have shown that Se layers on Ge have an intermediate resistance between that of ZnSe on Ge and pure Ge, and, therefore, the effect of additional phases practically does not worsen the passivating properties of the ZnSe layer on Ge.