Conductivity of ZnS: Mn nanocrystal layers with various Mn Ion concentrations

Transition metal-doped ZnS materials have received broad attention due to their well-known performance in electronics and optics. It has been observed previously by other researchers that Mn is one of interesting dopant. This dopant inside of ZnS offers a feasible means of fine tuning band gap. Because of this property, we interested to study the effect on electrical part. Hence, the aim of this work is discussed in term of electrical dark conductivity and photoconductivity of ZnS: Mn. Zn_(1-x)Mn_xS samples with various x values (0.05 ≤ x ≤ 0.35) are synthesized by using sol gel spin coating method. Surface morphology and I-V characteristics of the samples are investigated by using FE-SEM and dc electrical measurement with and without UV exposure. It is found that the average diameters are between 25 and 27 nm. The increase of Mn site doping concentration leads to an increase of the electrical dark conductivity and photoconductivity of the samples. Moreover, we have found that the current increases greater with the increment of Mn concentration by using UV source.