Light-Trapping-Enhanced Photodetection in Ge/Si Quantum Dot Photodiodes Containing Microhole Arrays with Different Hole Depths.

Photodetection based on assemblies of quantum dots (QDs) is able to tie the advantages of both the conventional photodetector and unique electronic properties of zero-dimensional structures in an unprecedented way. However, the biggest drawback of QDs is the small absorbance of infrared radiation due to the low density of the states coupled to the dots. In this paper, we report on the Ge/Si QD pin photodiodes integrated with photon-trapping hole array structures of various thicknesses.

Synergy between the Levels of Methylation of microRNA Gene Sets in Primary Tumors and Metastases of Ovarian Cancer Patients.

We studied the correlations between the levels of methylation of a group of 21 microRNA genes in 99 primary tumors and 29 macroscopic peritoneal metastases of ovarian cancer. Analysis of the level of methylation by quantitative methylation-specific PCR showed that co-methylation was detected for 13 pairs of microRNA genes in primary tumors and for 22 pairs in metastases. Pairs of microRNA genes that have shown significant co-methylation can be involved in common processes and pathways of gene regulation and interaction and can have common target genes.

Interdisk spacing effect on resonant properties of Ge disk lattices on Si substrates.

The light reflection properties of Ge disk lattices on Si substrates are studied as a function of the disk height and the gap width between disks. The interdisk spacing effect is observed even at such large gap widths as 500 nm. The gap width decrease leads to the appearance of the reflection minimum in the short wavelength region relative to one originated from the magnetic and electric dipole resonances in individual Ge disks, thereby essentially widening the antireflection properties.

Near-Infrared Photoresponse in Ge/Si Quantum Dots Enhanced by Photon-Trapping Hole Arrays.

Group-IV photonic devices that contain Si and Ge are very attractive due to their compatibility with integrated silicon photonics platforms. Despite the recent progress in fabrication of Ge/Si quantum dot (QD) photodetectors, their low quantum efficiency still remains a major challenge and different approaches to improve the QD photoresponse are under investigation. In this paper, we report on the fabrication and optical characterization of Ge/Si QD pin photodiodes integrated with photon-trapping microstructures for near-infrared photodetection.