Department of Radiophysics, National Research Tomsk State University, 36 Lenin Av., Tomsk 634050, Russian Federation.
Phys Chem Chem Phys. 2015 Nov 28;17(44):30052-6. doi: 10.1039/c5cp05192d. Epub 2015 Oct 26.
Experimental results indicate a particular importance of such a value as the equilibrium thickness of the wetting layer during epitaxial growth according to the Stranski-Krastanow mechanism in systems with a lattice mismatch. In this paper the change in free energy during the transition of atoms from the wetting layer to the island in such systems is considered. Recent experimental results also show that the surface energy of the island's facets depends upon the thickness of the deposited material. So, in this paper the equilibrium thickness of the wetting layer, at which transition from 2D to 3D growth becomes energetically favorable, is calculated with the assumption that the specific energy of the island's facets depends upon the wetting layer thickness. In this approximation a new generalized Muller-Kern formula is obtained. As an illustration of the proposed method, an example of a numerical calculation according to the new formula for the material system of germanium on a silicon (001) surface is given. The result for the found equilibrium thickness of the wetting layer is rather unexpected since it differs from the value obtained in the bounds of the traditional Muller-Kern model.
实验结果表明，在具有晶格失配的体系中，根据 Stranski-Krastanow 机制进行外延生长时，平衡润湿层厚度具有特殊的重要性。本文考虑了在从润湿层到岛的转变过程中原子的自由能变化。最近的实验结果还表明，岛的面的表面能取决于沉积材料的厚度。因此，本文假设岛的面的特定能量取决于润湿层的厚度，计算了从二维到三维生长变得在能量上有利的平衡润湿层厚度。在这种近似下，得到了一个新的广义 Muller-Kern 公式。作为所提出方法的说明，给出了根据新公式对锗在硅（001）表面上的材料系统进行数值计算的示例。所得到的平衡润湿层厚度的结果是出乎意料的，因为它与在传统 Muller-Kern 模型范围内得到的值不同。
