We show that both the morphology and the optoelectronic properties of SiGe islands growing in the pits of periodically pre-patterned Si(001) substrates are determined by the amount of Ge deposited per unit cell of the pattern. Pit-periods (p) ranging from 300 to 900 nm were investigated, and Ge growth was performed by molecular beam epitaxy (MBE) at temperatures of 690 and 760 °C. The ordered SiGe islands show photoluminescence (PL) emission, which becomes almost completely quenched, once a critical island volume is exceeded. By atomic force and transmission electron microscope images we identify the transition from pyramid-shaped to dome-shaped islands with increasing p. Eventually, the nucleation of dislocations in the islands leads to PL quenching. Below a critical Ge coverage a narrowing and a blue shift of the PL emission is observed, as compared to islands grown on a planar reference area of the same sample.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1088/0957-4484/22/16/165302 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Light-emitting diodes with Ge(Si) nanoislands embedded in photonic crystals.
Nanotechnology
February 2024
Institute for Physics of Microstructures of the Russian Academy of Sciences, 603950 Nizhny Novgorod, Russia.
Room temperature lateral p-i-nlight-emitting diodes (LEDs) with photonic crystals embedded in the i-region were fabricated on structures with Ge(Si) self-assembled islands and their optical properties were investigated. The use of preliminary amorphization and solid phase epitaxy of the implanted pand ncontact regions made it possible to reduce the impurity activation temperature from 800 °С-1100 °С to 600 °С, which corresponds to the growth temperature of Ge(Si) islands. This resulted in a significant reduction of the detrimental effect of the high-temperature annealing used for diode formation on the intensity and spectral position of the luminescence signal from the islands.
View Article and Find Full Text PDFDewetted, SiGe nanoparticles have been successfully exploited for light management in the visible and near-infrared, although their scattering properties have been so far only qualitatively studied. Here, we demonstrate that the Mie resonances sustained by a SiGe-based nanoantenna under tilted illumination, can generate radiation patterns in different directions. We introduce a novel dark-field microscopy setup that exploits the movement of the nanoantenna under the objective lens to spectrally isolate Mie resonances contribution to the total scattering cross-section during the same measurement.
View Article and Find Full Text PDFAdvanced preparation of plan-view specimens on a MEMS chip for TEM heating experiments.
MRS Bull
March 2022
Christian Doppler Laboratory for Nanoscale Phase Transformations, Center for Surface and Nanoanalytics, Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz, Austria.
Unlabelled: transmission electron microscopy (TEM) is a powerful tool for advanced material characterization. It allows real-time observation of structural evolution at the atomic level while applying different stimuli such as heat. However, the validity of analysis strongly depends on the quality of the specimen, which has to be prepared by thinning the bulk material to electron transparency while maintaining the pristine properties.
View Article and Find Full Text PDFDifferences between the global transcriptomes of Salmonella enterica serovars Dublin and Cerro infecting bovine epithelial cells.
BMC Genomics
July 2022
Environmental Microbial and Food Safety Laboratory, Beltsville Agricultural Research Center, USDA-ARS, Beltsville, MD, USA.
Background: The impact of S. enterica colonization in cattle is highly variable and often serovar-dependent. The aim of this study was to compare the global transcriptomes of highly pathogenic bovine-adapted S.
View Article and Find Full Text PDFCorrelation between sensitization to house dust mite major allergens, age, and symptoms in Japanese house dust mite allergic subjects.
Int Immunopharmacol
June 2022
Otorhinolaryngology and Head and Neck Surgery, Nippon Medical School, Tokyo, Japan.
Der p 23 has recently been recognized as a new house dust mite (HDM) major allergen that may be linked to the development of asthma in HDM allergic patients. This study aimed to investigate the frequency of sensitization to HDM major allergen components including Der p 23 and to examine the correlation between HDM-sensitization and AR symptom score in Japanese HDM allergic rhinitis (AR) patients without allergic asthma. Serum samples (n = 120) collected from Japanese HDM AR patients (12 to 64 years) without asthma were assessed for allergen-specific IgE (s-IgE) by ImmunoCAP (Dermatophagoides pteronyssinus (D.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!