Tensile-strained Ge/SiGe quantum wells for on-chip light emission
Abstract/Contents
- Abstract
- An efficient silicon (Si)-compatible light source is one of the most crucial building blocks for Si-based photonic integrated circuits. However, obtaining a high quality light source with emission wavelength around 1.55 um for coupling to the optical fiber network on a Si platform has proven extremely difficult since Si and other common materials compatible with existing Si processing technology have indirect band gaps, which are not desired for optoelectronic devices. Germanium (Ge) has attracted more and more attention in recent years due to its pseudo-direct band gap behavior and its compatibility with Si processing technology. In this dissertation, we explore and discuss the materials growth, optical properties and device design of Ge on a Si platform for silicon photonics. After discussing the Ge/SiGe quantum-well material growth techniques, we first demonstrate the enhanced direct-bandgap photoluminescence from Ge/SiGe quantum wells compared to bulk Ge, indicating that Ge/SiGe quantum-well material is a promising candidate for making an efficient light source on a Si platform. Then, we discuss the design of tensile-strained Ge/SiGe quantum-well microdisks for laser applications for silicon photonics. We fabricate suspended Ge/SiGe quantum-well microdisks with tensile strain by using an all-around silicon nitride stressor, on a Si substrate. A novel etch-stop technology is demonstrated that allows the capability of removing the defective buffer layer, as well as providing precise thickness control of the microdisks. The photoluminescence and Raman spectra indicate that we have achieved biaxial tensile-strain as high as 0.88% transferred from the silicon nitride stressor to the microdisks. Optical gain calculations show that positive net gain can be achieved in the gain medium of Ge quantum wells with 0.5% external biaxial tensile-strain at an electron doping concentration of 5x10^19 cm^{-3} and an injected carrier concentration of 2x10^19 cm^{-3}.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2016 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Chen, Xiaochi | |
|---|---|---|
| Associated with | Stanford University, Department of Electrical Engineering. | |
| Primary advisor | Harris, J. S. (James Stewart), 1942- | |
| Thesis advisor | Harris, J. S. (James Stewart), 1942- | |
| Thesis advisor | Kamins, Theodore I | |
| Thesis advisor | Saraswat, Krishna | |
| Advisor | Kamins, Theodore I | |
| Advisor | Saraswat, Krishna |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Xiaochi Chen. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2016. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2016 by Xiaochi Chen
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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