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稀磁GaMnAs外延膜中的Mn含量会影响外延膜的空穴浓度和应变弛豫.Raman散射研究表明,Mn含量为3%的超薄GaMnAs样品的空穴浓度大于2%样品,4%样品的空穴浓度小于3%样品.应变弛豫理论和高分辨X射线衍射研究表明,Mn含量为2%和3%的超薄GaMnAs外延层分别处于准共格或低弛豫状态,Mn含量为4%的GaMnAs外延层的弛豫度明显大于3%样品的弛豫度.我们认为,准共格或低弛豫度状态对空穴浓度随Mn含量的变化趋势几乎没有影响,较大弛豫度的应变状态将导致样品外延层产生较多缺陷,影响能带结构和能级,引起空穴浓度异常减小.
The Mn concentration in the diluted GaMnAs epitaxial films affects the hole concentration and strain relaxation in the epitaxial films.Raman scattering studies show that the hole concentration of the thin GaMnAs samples with 3% Mn content is larger than that of 2% and 4% Hole concentration of less than 3% samples.The strain relaxation theory and high resolution X-ray diffraction studies show that the epitaxial layer of ultra-thin GaMnAs with 2% and 3% Mn content are in quasi-coherent or low relaxation state respectively with Mn content of 4 % Relaxation of GaMnAs epitaxial layers is significantly greater than the relaxivity of 3% samples.We believe that the quasi-co-ordinate or low relaxation state of the hole concentration with Mn content trend has almost no effect, a larger relaxation Strain state will lead to more defects in the sample epitaxial layer, affecting the band structure and energy level, causing an abnormal decrease in hole concentration.