| 摘要 |
PURPOSE:To prevent a few carriers generated by the light irradiation from effluence and to improve the efficiency of a light conductivity effect by a method wherein a same conductivity type low resistance layer having a forbidden band width larger than a high resistance layer is installed. CONSTITUTION:A forward direction bias V1 is applied so that an n<+> type Ga1-x(3)Alx(3)As layer 3 side may be a positive and an n<+> type Ga1-x(1)Alx(1)As layer 1 side may be a negative. A light indicence of a wave length lambda1 is irradiated, electron, positive hole couples are generated in a Ga1-x(2)Alx(2)As layer 2. The generated electrons flow immediately to the outside of the layer 2 and the generated positive holes are enclosed within the layer 2 by the layer 1 having a larger forbidden band width and the layer 3 and they are efficiently captured by the previously induced positive hole trap in the layer 2. With this, the positive space electric charge is generated in the layer 2 and in order to catch this space charge, electrons flow in from the layer 1 into the layer 2 and the layer 2 posesses a conductivity, accordingly, the 1 element comes into an ON state under this state. |
