Crystal growth model for molecular beam epitaxy: Role of kinks on crystal growth

A simple crystal growth model for molecular beam epitaxy (MBE) is proposed. Based on the common features of various MBE material systems, growth modes are classified as either high-temperature growth or low-temperature growth. The transition temperature between the two growth modes is found to be a characteristic value: half the melting temperature (T m ) of each material. The incorporation of growing atoms on the crystal surface is discussed based on a crystal surface model composed of kinks, ledges, and terraces. At temperatures higher than 1/2 T m , kinks act as incorporation and decomposition sites for growing atoms, and the shape of the growth front step is simple and smooth. At temperatures lower than 1/2 T m , kinks act only as pinning sites with a zigzag step.