用椭圆偏振光谱法研究Ga_xIn_1-_xP的光学性质(Ⅱ)

STUDY ON THE OPTICAL PROPERTIES OF Ga x In 1 x P BY THE ELLIPSOMETRIC SPECTROSCOPY (Ⅱ)

用椭偏光谱法对用ＭＯＣＶＤ方法在ＧａＡｓ衬底上生长的ＧａｘＩｎ１－ｘＰ掺Ｓｉ及掺Ｚｎ样品在室温下，可见光区得到的光学常数求其介电函数三级微商谱．将用于分析调制反射谱的三点比例法推广，并用来分析介电函数的三级微商谱．精确地得到样品的带隙Ｅｇ，Ｅｇ＋△０以及Ｅｇ以上成对结构跃迁的能量位置及其间隔．计算了Ｅｇ以及费米能级的相对位置．将实验值与计算值比较，分析其差异的原因。

The optical constants of the doped Si or Zn Ga x In 1 x P samples grown by MOCVD on the GaAs substrates were measured at room temperature in the region of visible light by using the ellipsometric spectroscopy.The third derivative spectra of the optical constants were evaluated.Extending the threepoint scaling used in the analysis of the modulated reflective spectrum,the third derivative spectra of the dielectric functions can be analyzed.Thereby the accurate Eg,Eg+Δ 0 and the energy position and its gap of the paired structure above Eg.Were obtained.Eg and the position of the Fermi energy level were also calculated.The experimental and theoretical values were compared and the reason of difference between them was analyzed.The existence of ordered structure of samples was found.