| AVS 56th International Symposium & Exhibition | |
| Applied Surface Science | Tuesday Sessions |
| Session AS-TuP |
| Session: | Applied Surface Science Poster Session |
| Presenter: | V. D'Costa, Arizona State University |
| Authors: | V. D'Costa, Arizona State University Y. Fang, Arizona State University J. Menendez, Arizona State University J. Kouvetakis, Arizona State University |
| Correspondent: | Click to Email |
A tunable direct absorption edge has already been demonstrated in lattice-matched SiGeSn alloys grown on Ge-buffered Si [1]. These alloys represent the first practical group-IV ternary making it possible to decouple electronic structure and lattice parameter. This opens up new possibilities in IR optoelectronics and photovoltaics [2,3]. The d oping of ternary alloys is a basic requirement for device applications. N-type doping is achieved using (SiH3)3P whereas diborane is used to obtain p-type SiGeSn. In this paper, we focus on the transport properties of SiGeSn alloys. The dielectric function of heavily-doped alloys has been measured using infrared spectroscopic ellipsometry. The infrared response of the ternary alloys is Ge-like and is dominated by the free carrier contribution. In addition, the dielectric function of p-type alloys shows features due to optical transitions between split-off (SO), light-hole (LH), and heavy-hole (HH) bands. Our studies confirm that doping can be achieved in the ternary alloys. The resistivities and mobilities of the alloys are comparable to those found in Ge samples with similar doping concentrations. We are currently studying the transport properties of lattice-matched alloys as a function of Si and Sn concentration.
1. V.R. D’Costa et al, Phys. Rev. Lett 102, 107403 (2009)
2. R. A. Soref et al, Journal of Materials Research 22, 3281 (2007)
3. F. Dimroth and S. Kurtz, MRS Bull. 32, 230 (2007).