| 摘要 |
An electroluminescent diode comprises a semi-conductor portion with zones 11 and 12 defining pin junction 13 disposed symmetriclly in relation to hemispherical semi-conductor portion 14 of radius larger than any PN radiating face dimension, portion 14 having reduced impurity centre concentration and charge carrier concentration less than zones 11 and 12, this arrangement reducing internal absorptive <PICT:1101947/C4-C5/1> losses and total reflections. Zone 12 may be Te, Se, Si or Sn doped GaAs, zone 11, Zn doped GaAs; GaP and others amongst /sHAIII-BV compounds. The boundary between 12 and 14 may project in cylindrical form towards the PN junction and the part of 14 closed to 12 may be cylindrical and r/n deep, r being hemisphere radius, and n the refractive index of 14. In a method of preparation, a GaAs source with 2.1017 Te atoms/cc. heated to 1000 DEG C produces a 50a thick highly n-doped GaAs layer on a monocrystalline weakly n-conducting GaAs wafer at 800 DEG C. The PN junction is obtained by heating for 1 hour at 900 DEG C. with zinc. Round cylinders are stamped out, etched and ground. Alternatively, the PN junction may be produced by diffusing two doping substances into a low charge carrier concentrated semi-conductor producing opposite conductivity types. |
