Luminescence of defects in the structural transformation of layered tin dichalcogenides
Abstract
Layered tin sulfide semiconductors are both of fundamental interest and attractive for energy conversion applications. Sn sulfides crystallize in several stable bulk phases with different Sn:S ratios (SnS2, Sn2S3, and SnS), which can transform into phases with a lower sulfur concentration by introduction of sulfur vacancies (VS). How this complex behavior affects the optoelectronic properties remains largely unknown but is of key importance for understanding light-matter interactions in this family of layered materials. Here, we use the capability to induce VS and drive a transformation between few-layer SnS2 and SnS by electron beam irradiation, combined with in-situ cathodoluminescence spectroscopy and ab-initio calculations to probe the role of defects in the luminescence of these materials. In addition to the characteristic band-edge emission of the endpoint structures, our results show emerging luminescence features accompanying the SnS2 to SnS transformation. Comparison with calculations indicates that the most prominent emission in SnS2 with sulfur vacancies is not due to luminescence from a defect level but involves recombination of excitons bound to neutral VS in SnS2. These findings provide insight into the intrinsic and defect-related optoelectronic properties of Sn chalcogenide semiconductors.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 25, 2017
- Source ID
- 10.1063/1.5007060
Entities
People
- A. V. Krasheninnikov
- E. Sutter
- H.-p. Komsa
- Peter Sutter
- Yihe Huang
Organizations
- Aalto University
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Physics
- National University of Science and Technology
- Research Council of Finland
- United States Army
- United States Department of Energy
- University of Nebraska–Lincoln