| 摘要 |
PURPOSE:To evaluate non-destructively undoped GaAs crystal by using a semiconductor laser or light emitting diode as a light source for excitation and detecting the transmitted light of the laser luminous flux from a solid-state laser using an Nd:YAG crystal as a source for oscillation. CONSTITUTION:The absorption intensity of an undoped GaAs crystal is weak on the outside of an absorption end and the absorption occuring in a ''deep level'' forms a wide peak at 1.0-1.1mu wavelength. Since it is difficult to obtain a semiconductor laser having an oscillation wavelength in this wavelength region, a solid-state laser consisting of Nd:YAG to be excited by a semiconductor laser is used. The light 2 oscillated from a semiconductor laser 1 is condensed to an Nd: YAG crystal 4 and when conditions for excitation satisfy the conditions for oscillation, light 5 excited at 1.06mu is obtd. Such light 5 is condensed to a GaAs substrate crystal 7 to be examined and the light 8 transmitted through said crystal is detected by a detector 9, by which the crystal is evaluated. |
