SIGENET: Sigec nanostructures - a new path to silicon based optoelectronics

• Research unit: EU RFP
• Project number: 99.0078

Key words (English)

Quantum dots; quantum cascade structures; optoelectronics; epitaxy; silicon;
Education; Training; Scientific Research; Social Aspects

Alternative project number (English)

EU project number: HPRN-1999-00123

Research programs (English)

EU-programme: 5. Frame Research Programme - 4.1.1 Research training networks

Short description (English)

See abstract

Further information (English)

Full name of research-institution/enterprise:
Paul Scherrer Institut PSI
Labor für Mikro- und Nanotechnologie

Partners and International Organizations (English)

Coordinator: Johannes Kepler Universität, Linz (A)

Abstract (English)

In our comprehensive research effort the partners correlate data gathered by various structural, optical and electronic characterisation techniques to unravel the fundamental mechanisms in epitaxy of SiGeC nanostructures. Special emphasis is put on the input of strain modulations and chemical surface composition on the self-assembled quantum dot formation. This unique opportunity of using complementary experimental techniques as well as theory permits deeper insights into the driving mechanisms for dot formation and correlation phenomena of C-induced Gedots. The results will be used to optimise the epitaxy of quantum dots with respect to their size, density and distribution in order to tailor the radiative recombination paths of excitons confined in the dots. Besides the size and the density, also the chemical composition, the strain distribution and the interface abruptness will have an impact on the quantised states in the dots and hence their optical properties. In order to improve the luminescence efficiency the paths for non-radiative recombination have to be determined, which also depend on the structural properties. The role of the interstitial C on the structural and optical properties is certainly one of the crucial parameters to be investigated. Another one is the Ge segregation, e.g. the interface abruptness between the dots and the surrounding Si matrix.

It is generally believed that the size of the dots has to be in the range of a few nanometers to obtain efficient photon emission. The approach studied for efficient photon emission from Si based materials in the mid-infrared region will exploit intersubband transitions. Furthermore, intersubband spectroscopy in quantum well structures is suitable to study the impact of surfactants, like H and Sb, and the effect of C on the Ge segregation. The ambitious goal of the project is that the understanding of the correlation between structural, optical and electrical data enables us to design a fabrication process for Si-Ge-C nanostructures exhibiting efficient photon emission at room temperature. Ultimately the knowledge about the origins of the photoluminescence enhancement in Si-based nanostructures is anticipated to permit the development ofSi-based structures exhibiting electro-luminescence at room temperature.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 99.0078