| 摘要 |
PROBLEM TO BE SOLVED: To provide a transistor in which light deterioration is maximally suppressed and electric characteristics are stable.SOLUTION: By using an oxide semiconductor layer in which "safe" traps exist so that the oxide semiconductor layer exhibits two kinds of modes in light response, a transistor in which light deterioration is maximally suppressed and electric characteristics are stable can be achieved. The oxide semiconductor layer exhibiting the two kinds of modes in the light response has a photoelectric current value of 10 pA or more and 10 nA or less. Existence of the two kinds of modes in the light response can be confirmed from a fact that when average time τup to carrier capture by the "safe" traps is large enough, there are, in result of change in photoelectric current time, a region where the current value falls rapidly and a region where the current value falls gradually. |
