Growth of Inclined GaAs Nanowires by Molecular Beam Epitaxy: Theory and Experiment
1 Key Laboratory of Information Photonics and Optical Communications (Ministry of Education), Beijing University of Posts and Telecommunications, P.O. Box 66, 100876, Beijing, China
2 St.-Petersburg Academic University RAS, Khlopina 8/3, 194021, St.-Petersburg, Russia
3 Ioffe Physical-Technical Institute RAS, Politekhnicheskaya 26, 194021, St.-Petersburg, Russia
4 CNRS-LPN, Route de Nozay, 91460, Marcoussis, France
5 Department OptoGaN, Institut d’Electronique Fondamentale, UMR 8622 CNRS, 91405, Orsay Cedex, France
Nanoscale Research Letters 2010, 5:1692-1697 doi:10.1007/s11671-010-9698-7Published: 24 July 2010
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.