Atomic Model for the Unusual Gallium Growth Mode on the Ge(100) Surface
林卓穎1*, 林登松1
1Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
* presenting author:林卓穎,
In this study, we use the STM to explore the Ga growth mode on the Ge(100) surface. A small amount of Ga atoms develop like a chain on Ge surface along [110] direction in room temperature. With the deposition of Ga is increasing, Ga atoms will grow along [-110] direction, spreading like islands on the Ge(100). Until the deposition is 0.5 ML, the Ga atoms is 2 × 2 structure on the surface. When the deposition is over 0.5ML, the Ga clusters will appear. In the room temperature, the Ga/Ge(100) model is the same as Ga/Si(100) model.
Unlike the Ga/Ge(100) growth mode at room temperature, the Ge(100) was kept at 300 ˚C and deposited Ga atoms is a special phenomenon. We find the Ga atoms which hide on the edge of SA by using the different voltage which have different density of state. We propose a model to explain how’s the interaction between Ga and Ge atoms. At 300 ˚C, Ga atoms will take off and displace the Ge dimer regularity. After increasing the Ga atoms, the surface defect will increase, spreading like a negative island. In addition, the step edge of Ge become rough. When the deposition is great than 0.5 ML, the Ga island arrange on the surface orderly, which structure is 8 × n ( n= 4, 5 ). The Ge and Ga become alloy after the deposition is 4 ML.

Keywords: STM, Unusual Ga/Ge100 growth mode , Laser heating