GaAs structures with InAs and As quantum dots produced in a single molecular beam epitaxy process |
| |
Authors: | V N Nevedomskii N A Bert V V Chaldyshev V V Preobrazhenskii M A Putyato B R Semyagin |
| |
Affiliation: | (1) Photonics Research Center, School of Electrical & Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore;(2) Clean Room, School of Electrical & Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore; |
| |
Abstract: | Epitaxial GaAs layers containing InAs semiconductor quantum dots and As metal quantum dots are grown by molecular beam epitaxy.
The InAs quantum dots are formed by the Stranskii-Krastanow mechanism, whereas the As quantum dots are self-assembled in the
GaAs layer grown at low temperature with a large As excess. The microstructure of the samples is studied by transmission electron
microscopy. It is established that the As metal quantum dots formed in the immediate vicinity of the InAs semiconductor quantum
dots are larger in size than the As quantum dots formed far from the InAs quantum dots. This is apparently due to the effect
of strain fields of the InAs quantum dots upon the self-assembling of As quantum dots. Another phenomenon apparently associated
with local strains around the InAs quantum dots is the formation of V-like defects (stacking faults) during the overgrowth of the InAs quantum dots with the GaAs layer by low-temperature molecular
beam epitaxy. Such defects have a profound effect on the self-assembling of As quantum dots. Specifically, on high-temperature
annealing needed for the formation of large-sized As quantum dots by Ostwald ripening, the V-like defects bring about the dissolution of the As quantum dots in the vicinity of the defects. In this case, excess arsenic
most probably diffuses towards the open surface of the sample via the channels of accelerated diffusion in the planes of stacking
faults. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|