Photo-Response Analysis of Oxygenated Ge2Sb2Te5

Among various available phase-change materials, ternary chalcogenide Ge
2
Sb
2
Te
5
(GST) is the most popular one due to its excellent electrical and optical properties. Enormous investigations have been performed to alter or modulate its properties further by incorporating some foreign elements by various methods including oxygen. Oxygenated GST is of interest due to its higher compatibility with Si/SOI technology along with modulation in phase-change behavior for different photonic applications. This work presents the photodetection behavior of oxygenated GST in the simple metal-semiconductor-metal structure. The photo-response of the oxidized GST thin films in both the amorphous and crystalline phases has been measured. It is found that the electrical along with photo-conductivity of both phases of GST reduce upon the increasing extent of oxidation due to an increase in bonding lattices. A proper shifting of the bandgap has also been observed while increasing the amount of oxidation.