| 摘要 |
PURPOSE:To improve the current distribution of a light-emitting part and increase illuminance, by specifying the Al mixed crystal ratio in GaAlAs constituting a current diffusion layer. CONSTITUTION:An N-type AlGaInP light-emitting layer 103, a P-type current diffusion layer 105 composed of GaAlAs, etc., are deposited in order on an N-type GaAs single crystal substrate 101. The light-emitting layer 103 is doped with Se. The carrier concentration is 1X10<17>cm<-3>. The band gap energy is 2.2V. The film thickness is 1X10<-4>cm. The Al mixed crystal ratio in the current diffusion layer 105 is set in the range expressed by (0.872.Eg-1.391)<1/2>-0.094<=X<0.8 where Eg is the band gap energy of AlGaInP material turning to a light emitting layer, and X is the Al mixed crystal ratio of the GaAlAs current diffusion layer. That is, X=0.75. The current diffusion layer 105 is doped with Zn, and the P-type carrier concentration is 1X10<18>cm<-3>. The film thickness is 7X10<-4>cm. Thereby light absoption is not generated when the emission light wavelength is shorter than 593nm, so that illuminance can be improved. |
