Fabrication and properties characterization of BaSi2 thin-films thermally-evaporated on Ge (100) modified substrates

Highlights: • BaSi₂ thin-films are thermally-evaporated on modified Ge substrates. • Substrate modification has positive impact in improving properties of BaSi₂. • Implied short circuit current density of BaSi₂ on modified substrate is as high as 49 mA/cm². • Excess carrier-lifetime achieves 3.17 μs, among high values obtained for thin BaSi₂. - Abstract: The fabrication of orthorhombic barium disilicide (BaSi₂) thin-films on modified germanium (Ge) substrates by thermal evaporation method was demonstrated, in which the surface modification of Ge substrate was performed by a simple chemical etching method. The effects of etching time on crystalline quality and optical properties of the BaSi₂ films were investigated. The results revealed that the substrate modification has positive impact in improving the crystalline quality, reducing the light reflection, and increasing the absorption of the BaSi₂ thin-films. Etching time was optimized at 15 min, considering the trade-off between crystalline quality and optical properties. Minority carrier-lifetime of the evaporated film on Ge substrate achieved 3.17 μs, which is among the high value obtained for thin BaSi₂ films.