Growth of ZnSnO nano structures for thermopower applications by thermal evaporation with and without oxygen precursor

Abstract

In this manuscript, we have reported the crystal quality control of ZnSnO nanostructures during thermal evaporation growth in the presence and absence of oxygen gas during the growth process. To test this hypothesis, we have prepared two set of samples by evaporating Zn and tin powders (5:1 ratio) on Si substrate under similar growth conditions. But one set of samples was prepared in the presence of oxygen gas with a flow rate of 100sccm while other set of samples was grown under the absence of oxygen gas. Structural study revealed the formation of hexagonal structures of ZnSnO for both sets of samples while the Raman spectroscopy also supported the XRD data. But the observed morphology (SEM images) showed the different behavior of samples i. e porous structure of the samples grown using oxygen precursor while the nano-needle shape morphology was observed for the sample grown without oxygen. Thermo power measurements demonstrated that sample grown using oxygen precursor possess the highest value of Seebeck voltage along with other thermoelectric parameters when we compared with the samples grown without the presence of oxygen gas. The highest thermo power ability was related to the formation of porous structures which is a major cause of mobility enhancement.