Optical properties of Si1−xGex quantum dots grown using RPCVD

• Published in: Electronic materials letters 2011-06, Vol.7 (2), p.121-125
• Main Authors: Kang, S., Kil, Y. -H., Park, B. G., Choi, C. -J., Kim, T. S., Jeong, T. S., Shim, K. -H.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed Matter Physics; Materials Science; Nanotechnology; Nanotechnology and Microengineering; Optical and Electronic Materials
• ISSN: 1738-8090; 2093-6788
• DOI: 10.1007/s13391-011-0606-9

The optical properties of Si 1−x Ge x quantum dots (QDs) grown directly onto Si (001) substrates without a buffer layer using the reduced pressure chemical vapor deposition (RPCVD) system have been investigated. From the results of the EDX and XRD analyses of the Si 1−x Ge x QD structures, the Ge composition in the Si 1−x Ge x QDs was determined to be approximately 30% and 40%, for the respective analyses, and the values of the residual strain ɛ of the Si 0.7 Ge 0.3 and Si 0.7 Ge 0.4 samples were calculated as −0.0095 and −0.0089, respectively. Five peaks were observed in the Raman spectra, which correspond to the vibration of Si-Si, Si-Ge, and Ge-Ge phonons, and the Si 1−x Ge x QD related peaks were located at 486 cm −1 and 490 cm −1 . The transition peaks related to the QD region observed in the photocurrent spectrum were preliminarily assigned to the electron-heavy hole (e-hh) and electron-light hole (e-lh) transitions. The no-phonon (NP) peak of Si 1−x Ge x QDs was clearly observed in PL spectrum.