Disclosed is a method of manufacturing a thin film, the method including: growing an epitaxial layer on a surface of a wafer at a growth temperature, wherein the growing of the epitaxial layer comprises controlling a defect present on a surface of the wafer. More particularly, the method may include: selectively mixing the set of clock signals into a specific stage of a plurality of stages of the oscillator according to the set of digital weighting control signals. A plurality of nanowires are formed on a substrate, wherein the plurality of nanowires attached to the substrate comprises a nanowire forest.