Ge-on-Si light-emitting materials and devices for silicon photonics

The rapid growing needs for high data transmission bandwidth challenge the metal interconnection technology in every area from chip-level interconnects to long distance communication. Silicon photonics is an ideal platform for the implementation of optical interconnection capable of high bandwidth and low power consumption by integrating electronic and photonic devices on silicon. Many optical components in silicon photonics have been extensively studied, among which a silicon-based laser is arguably the most challenging element. This thesis mainly focuses on using engineered germanium as the optically active material for silicon-based light emitters with many potential benefits: Si-CMOS compatibility (both material and processing), electrical injection capability, and direct gap emission at technologically important 1.55 pm telecommunication band. Tensile-strained n+ germanium is capable of behaving like a direct band gap material owing to the direct band gap shrinkage upon tensile strain and the state-filling in the indirect L valleys with extrinsic electrons from n-type dopants. Our theoretical calculation using a direct band-to-band transition model has shown great benefit of tensile strain and n-type doping on the direct gap optical gain characteristics. By considering free carrier absorption which dominates the optical loss we have proven net gain can be achieved in 0.25% tensile-strained Ge with n-type doping concentration in a range of 1019 to mid-1020 cm-3. The injection threshold of the net gain is about 1018 cm-3 which can readily be achieved with either optical pumping or electrical pumping.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Sun, Xiaochen

Advisor dc:contributor.advisor

• Lionel C. Kimerling.

• Materials Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/53254

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/53254