Abstract:
A method for extracting state density in a band gap of an amorpous oxide semiconductor thin film transistor by using an optical differential ideality coefficient and a device thereof are provided. The method for extracting state density in a band gap of an amorpous oxide semiconductor thin film transistor includes a step of measuring a darkroom drain current from a darkroom according to a gate voltage and measuring a light reaction drain current according to the gate voltage by emitting light of a light source, a step of calculating a light reaction ideality coefficient and a darkroom ideality coefficient by using the light reaction drain current and the darkroom drain current, and a step of extracting the state density in the band gap of the thin film transistor based on the differentiation of the light reaction ideality coefficient and the darkroom ideality coefficient. The step of extracting the state density extracts genuine state density by de-embedding capacitance formed by free electrons. [Reference numerals] (AA) Start; (BB) End; (S310) Measure a darkroom drain current according to a gate voltage in a darkroom; (S320) Measure a light reaction drain current according to the gate voltage by emitting light of a light source; (S330) Calculate a darkroom ideality coefficient by using the darkroom drain current; (S340) Calculate a light reaction ideality coefficient by using the light reaction drain current; (S350) Calculate light reaction capacitance based on the differentiation of the light reaction ideality coefficient and the darkroom ideality coefficient; (S360) Extract state density from a band gap based on the light reaction capacitance