红外LED用掺硅HB-GaAs单晶纵向载流子浓度分布研究

GaAs单晶作为一种重要的LED衬底材料在光电器件中应用十分广泛,但载流子浓度(C.C.)分布不均、杂质浓度过高等缺陷会严重影响相关器件的性能.为制备纵向载流子浓度分布均匀的掺硅HB-GaAs单晶,本文探讨了单晶生长过程中熔区长度对纵向载流子浓度分布的影响.以高纯GaAs多晶为原料,设定不同的拉晶温度曲线,采用窄熔区技术进行晶体生长研究,最终生长出C.C.值分布更均匀、位错密度低(EPD≤10 000 cm-2)的<111>向N型掺硅GaAs单晶.利用辉光放电质谱法(GDMS)和范德堡法霍尔效应测试对晶体进行了表征,单晶纯度达到5N且无硼杂质沾污.     

PAC investigation of qudropole interaction in nano-soft magnetic material Fe73.5Cu1Nb3Si13.5B9

The quadrupole interaction in nano-soft magnetic material Fe_73.5Cu₁Nb₃Si_13.5B₉ has been studied by perturbed angular correlation using ⁶²Zn probe nuclei from the ISOL radioactive nuclear beam facility at CIAE HI-13 tandem accelerator. Two quadrupole interaction frequencies ω₀₁=440 Mrad/s with a distribution width σ=0 and ω₀₂=90 Mrad/s with a width σ=0.48 are obtained. The fractions of ω₀₁ and ω₀₂ are 38% and 62%, respectively. The measured quadruple interaction parameters indicate that 62% of the implanted ⁶²Zn are located in the grain boundary and 32% in the grain.