本論文研究是對成長於晶面(100)藍寶石基板上之AlN寬能隙化合物半導體磊晶薄膜,以Z-scan方法進行其非線性光學特性的研究。所使用的雷射光源為重覆率10Hz的Nd-YAG Q-Switch奈秒脈衝雷射的5倍頻光,光子能量為5.82eV (波長為213nm)略小於AlN的能隙6.2eV,及此雷射的2倍頻光,光子能量為2.33eV(波長為532nm)的兩種光源進行量測。經由「開孔徑」與「閉孔徑」兩種實驗架構,可分別得到AlN磊晶薄膜在雷射波長為213nm時,非線性吸收係數為1.075×104 cm/GW、非線性折射率為5.63×10-2 cm2/GW;在雷射波長為532nm時,非線性吸收係數為6.25×102 cm/GW、非線性折射率為6.7×10-3 cm2/GW。
This research use Z-scan method to measure and analysis the optical nonlinearity of epitaxy AlN films on sapphire substrate. The light source of Z-scan system is a 10Hz nanosecond Nd-YAG Q-switch 5HG (213nm) and SHG (532nm) laser. Its photon energy 5.82eV (wavelength: 213nm) is a little lower than AlN energy band gap 6.2eV. By the open aperture and close aperture experiment structure, we can get the nonlinear absorption coefficient and nonlinear refractive index of epitaxy AlN films. According to the results, the AlN films were abtained the nonlinear absorption coefficient is 1.075×104 cm/GW and the nonlinear refractive index is 5.63×10-2 cm2/GW at laser wavelength 213nm; the nonlinear absorption coefficient is 6.25×102 cm/GW and the nonlinear refractive index is 6.7×10-3 cm2/GW at laser wavelength 532nm.