By right of the prominent properties, Ge film grown on Si substrate plays an important role in the field of optoelectronic devices. However, the dislocation density of Ge film grown on Si substrate is still high due to the relatively large lattice mismatch between Ge and Si of ~4.18% that hinders the further development of devices. In this work, high-quality Ge film grown on Si substrate has been obtained based on study of the thermodynamic mechanism. On the one hand, the thermodynamic mechanism of Ge film on Si substrate by First-principle calculation based on density functional theory; and then high-quality Ge films were achieved on Si substrate by the low temperature and high temperature two-step growth technique by molecular beam epitaxy accordingly. The as-grown 2.0 μm-thick Ge film show high quality with a full-width at half-maximums for Ge(004) of 110 arcsec and very smooth surface with a root-mean-square roughness of 0.2 nm. The Ge film achieved in this work is a promising candidate for the fabrication of optoelectronic devices.

凭借突出的性能，在Si衬底上生长的Ge膜在光电器件领域起着重要作用。然而，由于Ge和Si之间的相对较大的晶格失配（约4.18％），阻碍了器件的进一步发展，在Si衬底上生长的Ge膜的位错密度仍然很高。在这项工作中，基于对热力学机理的研究，已经获得了在Si衬底上生长的高质量Ge膜。一方面通过基于密度泛函理论的第一性原理计算，研究了硅衬底上锗薄膜的热力学机理。然后通过分子束外延的低温和高温两步生长技术在Si衬底上获得高质量的Ge膜。成长中的2。0μm厚的Ge膜显示高质量，Ge（004）的半峰全宽为110 arcsec，表面非常光滑，均方根粗糙度为0.2 nm。在这项工作中获得的锗薄膜是光电子器件制造的有希望的候选者。