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A comparison of uniaxial and polyaxial suspended germanium bridges in terms of mechanical stress and thermal management towards a CMOS compatible light source

A comparison of uniaxial and polyaxial suspended germanium bridges in terms of mechanical stress and thermal management towards a CMOS compatible light source
A comparison of uniaxial and polyaxial suspended germanium bridges in terms of mechanical stress and thermal management towards a CMOS compatible light source
Germanium (Ge) is a promising candidate for a CMOS compatible laser diode.This is due to its compatibility with Silicon (Si) and its ability to be converted into a direct band gap material by applying tensile strain. In particular uniaxial suspended Ge bridges have been extensively explored due to their ability to introduce high tensile strain. There have been two recent demonstrations of low-temperature optically-pumped lasing in these bridges but no room temperature operation accredit to insufficient strain and poor thermal management. In this paper we compare uniaxial bridges with polyaxial bridges in terms of mechanical stress and thermal management using Finite Element Modelling (FEM). The stress simulations reveal that polyaxial bridges suffer from extremely large corner stresses which prevent larger strain from being introduced compared with uniaxial bridges. Thermal simulations however reveal that they are much less thermally sensitive than uniaxial bridges which may indicate lower optical losses. Bridges were fabricated and Raman spectroscopy was used to validate the results of the simulations. We postulate that polyaxial bridges could offer many advantages over their uniaxial counterparts as potential laser devices
1094-4087
27846-37858
Burt, Daniel
49c801a2-fb48-40f2-b72f-f713151b96e6
Gonzalez, Jofferson
e7280597-6d21-4025-bf30-19788675f225
Al-Attili, Abdelrahman
534a1c1f-3f8c-4a78-b71b-50c156e23373
Rutt, Harvey
e09fa327-0c01-467a-9898-4e7f0cd715fc
Khokhar, Ali
2eedd1cc-8ac5-4f8e-be25-930bd3eae396
Oda, Katsuya
7a476aa6-20a1-4d0a-938f-99d52720ae68
Gardes, Frederic
7a49fc6d-dade-4099-b016-c60737cb5bb2
Saito, Shinichi
14a5d20b-055e-4f48-9dda-267e88bd3fdc
Burt, Daniel
49c801a2-fb48-40f2-b72f-f713151b96e6
Gonzalez, Jofferson
e7280597-6d21-4025-bf30-19788675f225
Al-Attili, Abdelrahman
534a1c1f-3f8c-4a78-b71b-50c156e23373
Rutt, Harvey
e09fa327-0c01-467a-9898-4e7f0cd715fc
Khokhar, Ali
2eedd1cc-8ac5-4f8e-be25-930bd3eae396
Oda, Katsuya
7a476aa6-20a1-4d0a-938f-99d52720ae68
Gardes, Frederic
7a49fc6d-dade-4099-b016-c60737cb5bb2
Saito, Shinichi
14a5d20b-055e-4f48-9dda-267e88bd3fdc

Burt, Daniel, Gonzalez, Jofferson, Al-Attili, Abdelrahman, Rutt, Harvey, Khokhar, Ali, Oda, Katsuya, Gardes, Frederic and Saito, Shinichi (2019) A comparison of uniaxial and polyaxial suspended germanium bridges in terms of mechanical stress and thermal management towards a CMOS compatible light source. Optics Express, 27 (26), 27846-37858. (doi:10.1364/OE.27.037846).

Record type: Article

Abstract

Germanium (Ge) is a promising candidate for a CMOS compatible laser diode.This is due to its compatibility with Silicon (Si) and its ability to be converted into a direct band gap material by applying tensile strain. In particular uniaxial suspended Ge bridges have been extensively explored due to their ability to introduce high tensile strain. There have been two recent demonstrations of low-temperature optically-pumped lasing in these bridges but no room temperature operation accredit to insufficient strain and poor thermal management. In this paper we compare uniaxial bridges with polyaxial bridges in terms of mechanical stress and thermal management using Finite Element Modelling (FEM). The stress simulations reveal that polyaxial bridges suffer from extremely large corner stresses which prevent larger strain from being introduced compared with uniaxial bridges. Thermal simulations however reveal that they are much less thermally sensitive than uniaxial bridges which may indicate lower optical losses. Bridges were fabricated and Raman spectroscopy was used to validate the results of the simulations. We postulate that polyaxial bridges could offer many advantages over their uniaxial counterparts as potential laser devices

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Accepted/In Press date: 8 November 2019
e-pub ahead of print date: 13 December 2019
Published date: 23 December 2019

Identifiers

Local EPrints ID: 435939
URI: http://eprints.soton.ac.uk/id/eprint/435939
ISSN: 1094-4087
PURE UUID: aea54f9b-7c97-42f6-8159-43e01f5d0f2c
ORCID for Shinichi Saito: ORCID iD orcid.org/0000-0003-1539-1182

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Date deposited: 25 Nov 2019 17:30
Last modified: 07 Oct 2020 03:36

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