Abstract
Self-assembled InN nanocolumns were grown at low temperatures by plasma-assisted molecular beam epitaxy with a high crystalline quality. The self-assembling procedure was carried out on AlN/Al layers on Si(111) substrates avoiding the masking process. The Al interlayer on the Si(111) substrate prevented the formation of amorphous SiN. We found that the growth mechanism at of InN nanocolumns started by a layer-layer (2D) nucleation, followed by the growth of 3D islands. This growth mechanism promoted the nanocolumn formation without strain. The nanocolumnar growth proceeded with cylindrical and conical shapes with heights between 250 and 380 nm. Detailed high-resolution transmission electron microscopy analysis showed that the InN nanocolumns have a hexagonal crystalline structure, free of dislocation and other defects. The analysis of the phonon modes also allowed us to identify the hexagonal structure of the nanocolumns. In addition, the photoluminescence spectrum showed an energy transition of at for the InN nanocolumns, confirmed by photoreflectance spectroscopy.
Highlights
InN is a direct band-gap semiconductor with interesting physical properties such as; an infrared band-gap energy [1,2], a small electron effective mass [3,4], a high electronic mobility [5,6] and radiation resistance [7]
We report on the growth of InN nanocolumns (InN NCs) at a growth temperature of 400 ◦ C
The growths were carried out in a Riber C21 MBE system equipped with a radio frequency (RF)
Summary
InN is a direct band-gap semiconductor with interesting physical properties such as; an infrared band-gap energy [1,2], a small electron effective mass [3,4], a high electronic mobility [5,6] and radiation resistance [7]. Important technological applications of this material include infrared light emitting diodes, high-speed and high-frequency devices, and photovoltaic systems [5]. To develop the above-mentioned devices, InN with a high crystalline quality is required. InN films commonly present a low crystal quality mainly caused by the low dissociation temperature and the lack of lattice-matched substrates [8]. These problems can be avoided with the growth of InN nanocolumns (InN NCs), where the lateral stress relaxation at sidewalls allows obtaining defect-free and strain-free nanostructures [9,10,11,12].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
