| 摘要 |
PURPOSE:To improve the luminous efficiency of an active layer by a method wherein the titled element is equipped with a hetero junction structure that the active layer consisting of a semiconductor layer of a small band gap energy is sandwiched by the first and second clad layers composed of an N type and a P type semiconductor layer and wherein the impurity concentration is more increased as the region goes more distant from the hetero interface between at least one of the clad layers and the active layer. CONSTITUTION:Using S doped InP in the N type clad layer 12, InGaAsP emitting light at the wavelength of 1.3mum as the active layer 13, and Zn doped InP in the P type clad layer 14, the impurity concentration of said layer 12 is set at 2.8X10<18>cm<-3>, that of said layer 14 at 3.2X10<17>cm<-3> in the hetero interface 16 between the active layer 13 and said clad layer 14, while said layer 14 is grown so that the impurity reaches 3X10<18>cm<-3> during increase in the direction of layer thickness, impurity modulated doping is performed by making the impurity amount varied. With this sample, the luminous efficiency is largely improved at 1.5 times conventional in the luminous intensity of photo luminescence and about 1.4 times in the luminous amount. |
