SIN^+GaAs结构中的Franz-Keldysh振荡的傅里叶变换研究

FOURIER TRANSFORMATION STUDY OF THE FRANZ-KELDYSH OSCILLATION IN SIN^+ GaAs STRUCTURES 

利用傅里叶变换 (FT)方法 ,对Franz Keldysh振荡 (FKO)的理论线性作了详细的数值模拟 ,并用光调制反射谱(PR)测量了一组本征层 (I层 )厚度不同的表面 本征层 n型重掺杂层 (SIN+ )结构的GaAs样品的FKO .PR谱的FT分析表明 ,一部分样品的FT谱 ,包括其实部、虚部和模 ,与理论线性符合得比较好 ,由此求出轻空穴 (LH)和重空穴 (HH)的约化质量平方根之比 μl/ μh对不同样品在 0 80 5— 0 816之间 ,同时也可以求出样品中的内建电场强度F1,和调制光引起的调制电场δF =F1-F2 .有一些样品的FT谱实部和虚部与理论线性差别很大 ,用FT的模仍可以给出有用的信息 .

Fourier transformation (FT) method has been used in the theoretical lineshape analysis of the Franz\|Keldysh Oscillation (FKO) in detail by numerical simulation.The FKO of a set of GaAs SIN\++ samples was obtained in photoreflectance measurements.The FT spectra of a part of the samples,including of the real part,imaginary part,and mode of the FT,are well consistent with the theoretical lineshapes.The ratio of the square root of the reduced mass of the light hole (LH) to the heavy hole (HH),μ l/μ h,obtained in the analysis was in the range of 0 805 to 0 816 for different samples.In addition,the built\|in electric field F 1,and the modulation field δF=F\-1-F\-2 induced by photo\|modulation were also obtained in the analysis.However,for a few samples great difference was found in the lineshape of the real part and imaginary part of their FT spectra from the theoretical lineshape.In this case the mode of the FT spectra still can be used to obtain useful information.