摘要 |
PURPOSE:To separate lights of three or more wavelengths without necessity of mechanical accuracy by providing wavelength selective transmission in a semiconductor multilayer structure which contains a semiconductor superlattice structure, and modulating the density of two-dimensional electron gas of hetero junction with the transmitting light. CONSTITUTION:A semiconductor multilayer structure 4 that the third and fourth semiconductor layers 4A, 4B of different forbidden band widths are alternately laminated on a hetero junction layer 3 formed of the light absorbing first semiconductor layer 2 and two-dimensional electron gas supplying second semiconductor layer having larger forbidden band width than the layer 2 is formed. At this time, selective wavelength is provided by altering the repeating pitch of the layers 4A, 4B and the mixed crystal value. Further, the thickness of the layers of the structure 4 is reduced as a superlattice structure to generate an exiton level. The specific wavelength is selectively transmitted in the structure 4, the density of the two-dimensional electron gas generated in the hetero junction boundary of the layer 2 is modulated to discriminate the wavelength. |