Fabrication and optical properties of multishell InAs quantum dots on GaAs nanowires

Abstract

Hybrid nanostructures combining nanowires with quantum dots promote the development of nanoelectronic and nanophotonic devices with integrated functionalities. In this work, we present a complex nanostructure with multishell quantum dots grown on nanowires. 1–4 shells of Stranski-Krastanov InAs quantum dots are grown on the sidewalls of GaAs nanowires by metal organic chemical vapor deposition. Different dot shells are separated by 8 nm GaAs spacer shells. With increasing the number of shells, the quantum dots become sparser and tend to align in one array, which is caused by the shrinkage of facets on which dots prefer to grow as well as the strain fields produced by the lower set of dots which influences the migration of In adatoms. The size of quantum dots increases with the increase of shell number due to enhanced strain fields coupling. The spectra of multishell dots exhibit multiwavelength emission, and each peak corresponds to a dot shell. This hybrid structure may serve as a promising element in nanowire intermediate band solar cells, infrared nanolasers, and photodetectors.

Photovoltaic Performance of a Nanowire/Quantum Dot Hybrid Nanostructure Array Solar Cell

“…In our previous study [ 15 ], the fabrication of the NW/QD hybrid structures was realized by using a Thomas Swan Close Coupled Showerhead (CCS) metal organic chemical vapor deposition (MOCVD) system. Trimethylgallium (TMGa), trimethylindium (TMIn), and arsine (AsH 3 ) were used as precursors.…”

“…This may be achieved by increasing the number of QDs, by enhancing the optical absorption, or a combination of both [ 14 ]. In recent years, an attractive structure has been fabricated by growing Stranski-Krastanov (S-K) QDs on the sidewalls of nanowires (NWs), which offers an innovative approach to combine the advantage of the two kinds of nanostructures [ 15 – 19 ]. Multilayer QDs can be grown on the sidewalls of NWs, which substantially increase the number of QDs, while the vertically aligned NW array can dramatically enhance the absorption of QDs due to the excellent light-trapping ability [ 20 – 24 ].…”