Near-IR multi-quantum-well SiGe detectors show promise for photonics integration

High-quality single-crystal silicon-germanium (SiGe) multi-quantum-well layers were epitaxially grown on silicon substrates by researchers at Bilkent University (Ankara, Turkey), the Massachusetts Institute of Technology (Cambridge, MA), Korea University (Seoul, South Korea), and the Masdar Institute of Science and Technology (Abu Dhabi, UAE). The layers were fashioned into mesa-structured p-i-n photodetectors functioning at telecommunications wavelengths with reverse leakage currents of about 10 mA/cm2 and responsivities above 0.1 A/W in the 1300 to 1600 nm range. The spectral response of the photodetectors was voltage-tunable via altering the reverse bias, shifting the absorption edge by tens of nanometers.

The creation of GeSi devices on silicon is important for large-scale optical and optoelectronic circuits, as SiGe fabrication is compatible with complementary metal-oxide semiconductor (CMOS) technologies used to fabricate silicon computer chips. The ten quantum wells for the p-i-n detectors consisted of 10-nm-thick germanium wells and 20-nm-thick Si0.1Ge0.9 barriers, with the strained germanium lattice contributing to a high light absorption. Photodiodes were made with mesa diameters ranging between 20 and 120 μm; for devices with mesa areas less than 100 μm2, the RC time constant was estimated to be below one picosecond. Contact Ali Okyay at

Most Popular Articles


Opportunities in the Mid-IR

The technology for exploiting the mid-IR is developing rapidly:  it includes quantum-cascade lasers and other sources, spectroscopic instruments of many...
White Papers

Introduction to scientific InGaAs FPA cameras

Working in the near infrared (NIR) and shortwave infrared (SWIR) regions of the spectrum offers r...
Technical Digests

REMOTE FIBER-OPTIC SENSING: Data in abundance from difficult environments

The use of optical fibers to measure strain, temperature, and other parameters at desired points ...

SCANNERS FOR MATERIALS PROCESSING: Serving demanding applications

Galvanometer-based scanners are an essential component in laser-based materials-processing system...

OPTICAL COATINGS: Evolving technology produces new benefits

The antireflection, high-reflection, and/or spectral characteristics provided by optical coatings...

FREEFORM OPTICS: Top-notch capabilities lead to expanded possibilities

The use of free-form aspherical surfaces in an optical system can give it abilities impossible to...

Click here to have your products listed in the Laser Focus World Buyers Guide.


AFL Secures Patent for OTDR Technology

10/03/2013 AFL has been awarded a patent for “Optical Time Domain Reflectometer,” US Patent 8,411,259. The p...
Social Activity
Copyright © 2007-2015. PennWell Corporation, Tulsa, OK. All Rights Reserved.PRIVACY POLICY | TERMS AND CONDITIONS