An oxide semiconductor composition for use in thin film transistors includes indium oxide, zinc oxide, and an oxide including a doping element of scandium, such as scandium oxide. A molar percentage of the indium oxide can be larger than approximately 50%. The oxide semiconductor composition can have a formula of In2Sc2ZnO7. Manufacturing of the oxide semiconductor composition can include: mixing indium oxide powder, scandium oxide powder, and zinc oxide powder to thereby obtain an oxide shaped object; and sintering the oxide shaped object to form the oxide semiconductor composition. A thin-film transistor for use in a semiconductor device, such as a display apparatus, can include the oxide semiconductor composition, and can thereby have improved mobility of the oxide semiconductor due to the reduced oxygen vacancy therein.