Infrared absorption of n-type tensile-strained Ge-on-Si
We analyze the IR absorption of tensile-strained, n-type Ge for Si-compatible laser applications. A strong intervalley scattering from the indirect L valleys to the direct Γ valley in n[superscript +] Ge-on-Si is reported for the first time to our knowledge. The intervalley absorption edge is in goo...
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| Format: | Article |
| Language: | en_US |
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Optical Society of America
2013
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| Online Access: | http://hdl.handle.net/1721.1/79736 https://orcid.org/0000-0002-3913-6189 |
| _version_ | 1811076123287617536 |
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| author | Wang, Xiaoxin Li, Haofeng Cai, Yan Kimerling, Lionel C. Michel, Jurgen Liu, Jifeng Camacho-Aguilera, Rodolfo Ernesto |
| author2 | MIT Materials Research Laboratory |
| author_facet | MIT Materials Research Laboratory Wang, Xiaoxin Li, Haofeng Cai, Yan Kimerling, Lionel C. Michel, Jurgen Liu, Jifeng Camacho-Aguilera, Rodolfo Ernesto |
| author_sort | Wang, Xiaoxin |
| collection | MIT |
| description | We analyze the IR absorption of tensile-strained, n-type Ge for Si-compatible laser applications. A strong intervalley scattering from the indirect L valleys to the direct Γ valley in n[superscript +] Ge-on-Si is reported for the first time to our knowledge. The intervalley absorption edge is in good agreement with the theoretical value. On the other hand, we found that the classical λ[superscript 2]-dependent Drude model of intravalley free-carrier absorption (FCA) breaks down at λ < 15 μm. A first-principle model has to be employed to reach a good agreement with the experimental data. The intravalley FCA loss is determined to be <20 cm[superscript −1] for n = 4 × 10[superscript 19] cm[superscript −3] at λ = 1.5–1.7 μm, an order lower than the results from Drude model. The strong L → Γ intervalley scattering favors electronic occupation of the direct Γ valley, thereby enhancing optical gain from the direct gap transition of Ge, while the low intravalley free-electron absorption at lasing wavelengths leads to low optical losses. These two factors explain why the first electrically pumped Ge-on-Si laser achieved a higher net gain than the theoretical prediction using λ[superscript 2]-dependent free-carrier losses of bulk Ge and indicate the great potential for further improvement of Ge-on-Si lasers. |
| first_indexed | 2024-09-23T10:16:34Z |
| format | Article |
| id | mit-1721.1/79736 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:16:34Z |
| publishDate | 2013 |
| publisher | Optical Society of America |
| record_format | dspace |
| spelling | mit-1721.1/797362022-09-26T16:54:42Z Infrared absorption of n-type tensile-strained Ge-on-Si Wang, Xiaoxin Li, Haofeng Cai, Yan Kimerling, Lionel C. Michel, Jurgen Liu, Jifeng Camacho-Aguilera, Rodolfo Ernesto MIT Materials Research Laboratory Massachusetts Institute of Technology. Department of Materials Science and Engineering Massachusetts Institute of Technology. Microphotonics Center Camacho-Aguilera, Rodolfo Ernesto Cai, Yan Kimerling, Lionel C. Michel, Jurgen We analyze the IR absorption of tensile-strained, n-type Ge for Si-compatible laser applications. A strong intervalley scattering from the indirect L valleys to the direct Γ valley in n[superscript +] Ge-on-Si is reported for the first time to our knowledge. The intervalley absorption edge is in good agreement with the theoretical value. On the other hand, we found that the classical λ[superscript 2]-dependent Drude model of intravalley free-carrier absorption (FCA) breaks down at λ < 15 μm. A first-principle model has to be employed to reach a good agreement with the experimental data. The intravalley FCA loss is determined to be <20 cm[superscript −1] for n = 4 × 10[superscript 19] cm[superscript −3] at λ = 1.5–1.7 μm, an order lower than the results from Drude model. The strong L → Γ intervalley scattering favors electronic occupation of the direct Γ valley, thereby enhancing optical gain from the direct gap transition of Ge, while the low intravalley free-electron absorption at lasing wavelengths leads to low optical losses. These two factors explain why the first electrically pumped Ge-on-Si laser achieved a higher net gain than the theoretical prediction using λ[superscript 2]-dependent free-carrier losses of bulk Ge and indicate the great potential for further improvement of Ge-on-Si lasers. APIC Corporation. Fully LASER Integrated Photonics (FLIP) Program Naval Air Warfare Center (U.S.). Aircraft Division (OTA N00421-03-9-0002) 2013-07-30T19:00:06Z 2013-07-30T19:00:06Z 2013-02 2013-01 Article http://purl.org/eprint/type/JournalArticle 0146-9592 1539-4794 http://hdl.handle.net/1721.1/79736 Wang, Xiaoxin et al. “Infrared Absorption of N-type Tensile-strained Ge-on-Si.” Optics Letters 38.5 (2013): 652. © 2013 Optical Society of America https://orcid.org/0000-0002-3913-6189 en_US http://dx.doi.org/10.1364/OL.38.000652 Optics Letters Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Optical Society of America MIT web domain |
| spellingShingle | Wang, Xiaoxin Li, Haofeng Cai, Yan Kimerling, Lionel C. Michel, Jurgen Liu, Jifeng Camacho-Aguilera, Rodolfo Ernesto Infrared absorption of n-type tensile-strained Ge-on-Si |
| title | Infrared absorption of n-type tensile-strained Ge-on-Si |
| title_full | Infrared absorption of n-type tensile-strained Ge-on-Si |
| title_fullStr | Infrared absorption of n-type tensile-strained Ge-on-Si |
| title_full_unstemmed | Infrared absorption of n-type tensile-strained Ge-on-Si |
| title_short | Infrared absorption of n-type tensile-strained Ge-on-Si |
| title_sort | infrared absorption of n type tensile strained ge on si |
| url | http://hdl.handle.net/1721.1/79736 https://orcid.org/0000-0002-3913-6189 |
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