Naslov
Ge/Si core/shell quantum dots in alumina: tuning the optical absorption by the core and shell size

Autori
Nekić, Nikolina ; Sancho-Parramon, Jordi ; Bogdanović Radović, Ivančica ; Grenzer, Joerg ; Huebner, Rene ; Bernstorff, Sigrid ; Ivanda, Mile ; Buljan, Maja

Izvornik
Nanophotonics (2192-8606) 6 (2017), 5; 1055-1062

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Ge/Si core/shell quantum dots ; quantum confinement ; absorption ; self-assembly

Sažetak
Ge/Si core/shell quantum dots (QDs) recently received extensive attention due to their specific properties induced by the confinement effects of the core and shell structure. They have a type II confinement resulting in spatially separated charge carriers, the electronic structure strongly dependent on the core and shell size. Herein, the experimental realization of Ge/Si core/shell QDs with strongly tunable optical properties is demonstrated. QDs embedded in an amorphous alumina glass matrix are produced by simple magnetron sputtering deposition. In addition, they are regularly arranged within the matrix due to their self-assembled growth regime. QDs with different Ge core and Si shell sizes are made. These core/shell structures have a significantly stronger absorption compared to pure Ge QDs and a highly tunable absorption peak dependent on the size of the core and shell. The optical properties are in agreement with recent theoretical predictions showing the dramatic influence of the shell size on optical gap, resulting in 0.7 eV blue shift for only 0.4 nm decrease at the shell thickness. Therefore, these materials are very promising for light-harvesting applications.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA