非晶锗的低温晶化和光学特性研究(英文)

Study on the Low Temperature Crystallization and Optical Properties of Amorphous Ge Films

本文采用直流磁控溅射在(100)硅衬底上沉积了单层锗薄膜,分别用拉曼光谱和X射线衍射研究了薄膜的结晶性,通过对结晶性的研究发现,在衬底温度为200℃时溅射功率为150W时结晶性开始变好,功率增至250W的过程,锗薄膜的择优取向发生(220)向(331)的变化。这样在无金属掺杂的情况下得到了结晶性较好的样品。光致发光结果表明,非晶锗在可见光区有较强的发光现象,发光峰位中心分别在648.1nm和713.0nm。发光峰位不随晶粒尺寸变化而变化,但峰强对晶粒大小的依赖性很强,平均晶粒较大的锗薄膜在可见光区发光现象不显著。

A series of germanium films were fabricated by DC magnetron sputtering technique on silicon （100） substrates at various sputtering powers. The crystallized films of Ge was grown at temperatures about 200℃ without incorporating any metals. The germanium films were characterized by X-ray diffraction, Raman spectroscopy （laser excitation wavelength： 514.5nm） and photoluminescence. The films grown below 150W were amorphous, while those above 150W were polycrystalline. The photoluminescence （PL） spectra of amorphous samples consist of two emission peaks centered at 648. lnm and 713.0nm. The intensities of PL peaks decrease with increasing grain size but the PL bands show no significant dependence on grain size.