Patent ID: 6111904
Filing Date: 2000-08-29
Classification: B82Y,H01S

Abstract:
An active layer structure provided in a light emission device for emitting a light with a predetermined wavelength, said active layer structure comprising:a multiple quantum well structure comprising alternating laminations of first well layers showing electroluminescence and potential barrier layers, said first well layers having a first set of energy band gaps which are uniform and corresponds to said predetermined wavelength, provided that energy band gap is defined as a difference between a ground level of electrons in conduction band and a ground level of holes in valence band; andat least a second well layer being provided within any of said potential barrier layers so that said second well layer is separated via said potential barrier layers from said first well layers,wherein said second well layer has a second energy band gap in a range which is above said first set of energy band gaps and below a set of forbidden band widths of said potential barrier layers, andwherein said range of said second energy band gaps is defined so that said second well layer exhibits carrier accumulations and no electroluminescence to thereby ensure that carriers accumulated in said second well layer are injected into said first well layers when said first well layers are deficient in carriers for said electroluminescence.