Dislocation-free axial InAs-on-GaAs nanowires on silicon

作者：Beznasyuk Daria V^*; Robin Eric; Den Hertog Martien; Claudon Julien; Hocevar Moira

来源：Nanotechnology, 2017, 28(36): 365602.

DOI：10.1088/1361-6528/aa7d40

• nanowires
• heterostructures
• molecular beam epitaxy
• transmission electron miscroscopy
• III-V semiconductor
• silicon
• interface

We report on the growth of axial InAs-on-GaAs nanowire heterostructures on silicon by molecular beam epitaxy using 20 nm diameter Au catalysts. First, the growth parameters of the GaAs nanowire segment were optimized to achieve a pure wurtzite crystal structure. Then, we developed a two-step growth procedure to enhance the yield of vertical InAs-on-GaAs nanowires. We achieved 90% of straight InAs-on-GaAs nanowires by further optimizing the growth parameters. We investigated the composition change at the interface by energy dispersive x-ray spectroscopy and the nanowire crystal structure by transmission electron microscopy. The composition of the nominal InAs segment is found to be InxGa1-xAs with x = 0.85 and corresponds to 6% of lattice mismatch with GaAs. Strain mapping performed by the geometrical phase analysis of high-resolution images revealed a dislocation-free GaAs/In0.85Ga0.15As interface. In conclusion, we successfully fabricated highly mismatched heterostructures, confirming the prediction that axial GaAs/In0.85Ga0.15As interfaces are pseudomorphic in nanowires with a diameter smaller than 40 nm.

• 出版日期2017-9-8
• 单位中国地震局