Zhang X, Dubrovskii V G, Sibirev N V, Cirlin G E, Sartel C, Tchernycheva M, Harmand J C, Glas F
Nanoscale Res Lett. 2010 Jul 24;5(10):1692-7. doi: 10.1007/s11671-010-9698-7.
The growth of inclined GaAs nanowires (NWs) during molecular beam epitaxy (MBE) on the rotating substrates is studied. The growth model provides explicitly the NW length as a function of radius, supersaturations, diffusion lengths and the tilt angle. Growth experiments are carried out on the GaAs(211)A and GaAs(111)B substrates. It is found that 20° inclined NWs are two times longer in average, which is explained by a larger impingement rate on their sidewalls. We find that the effective diffusion length at 550°C amounts to 12 nm for the surface adatoms and is more than 5,000 nm for the sidewall adatoms. Supersaturations of surface and sidewall adatoms are also estimated. The obtained results show the importance of sidewall adatoms in the MBE growth of NWs, neglected in a number of earlier studies.
研究了在旋转衬底上通过分子束外延（MBE）生长倾斜砷化镓纳米线（NWs）的过程。该生长模型明确给出了纳米线长度与半径、过饱和度、扩散长度以及倾斜角的函数关系。在砷化镓（211）A和砷化镓（111）B衬底上进行了生长实验。结果发现，倾斜20°的纳米线平均长度是原来的两倍，这是由于其侧壁上的原子沉积速率更高所致。我们发现，对于表面吸附原子，550°C时的有效扩散长度为12纳米，而对于侧壁吸附原子，有效扩散长度超过5000纳米。还估算了表面和侧壁吸附原子的过饱和度。所得结果表明，侧壁吸附原子在纳米线的分子束外延生长中具有重要作用，而这在许多早期研究中被忽视了。
