| 摘要 |
PURPOSE:To obtain an optically bistable device of a high light-extinction ratio at low energy consumption by making use of an internal field effect to a quantum well generated by spatial isolation of a photo-excitation carrier by a method wherein a hole barrier layer and an electron barrier layer in a neutral state are arranged alternately between two or more quantum well layers. CONSTITUTION:In a superlattice semiconductor material, hole barrier layers 2 and electron barrier layers 3 are arranged alternately between two or more quantum well layers 1. If the light of low energy of about 10 meV is irradiated from an absorption edge of a quantum well, a small number of electrons and holes are generated at the quantum well layers 1 because the coefficient of absorption is small; these electrons and holes are immediately isolated spatially by an action of the hole barrier layers 2 and the electron barrier layers 3 which sandwich the individual quantum well layers 1. As a result, an electric field is generated inside the quantum well layers and the coefficient of absorption with reference to the incident light is increased by the stark effect; the electric field which is exerted on the individual quantum well layers 1 is strengthened still more. By repeating these mechanism cycles, the optical bistability is realized between individual strength values of the outgoing light. |
