Panthani Si-Nanosheet Research

Using a full array of combined scientific techniques, Department of Chemical and Biological Engineering associate professor and Herbert L. Stiles Faculty Fellow Matthew Panthani and his research team are rethinking the way science is exploring the applications of Si-nanosheets (silicon nanosheets – SiNSs).

The work was recently published as a cover story in the journal Chemistry of Materials (Vol. 32, No. 2, January 28, 2020), “Silicene, Siloxene, or Silicane? Revealing the Structure and Optical Properties of Silicon Nanosheets Derived from Calcium Disilicide.”

Lead investigator Panthani, Iowa State CBE assistant professor Luke T. Roling, and Iowa State chemical engineering graduate student Bradley Ryan and then-graduate students Utkarsh Ramesh, Rainie Nelson and Yujie Wang are among the authors.

A nanosheet is a two-dimensional nanostructure with a thickness between one and 100 millimeters. Because of unique electrical and chemical properties compared to much larger-scale materials, nanosheets have become a fast-growing segment of nanoscale applications in industry. Since 2017 Si-nanosheets have been used as a prototype material for the next generation of many processes, including electronic, optoelectronic, spintronic, and catalytic, which have many potential industrial applications.

The paper discusses the fact that though Si-nanosheets were first synthesized more than 150 years ago, there is a lack of consensus in scientific literature regarding the structure and optical properties of the material. The Panthani group project has provided conclusive evidence of the structural and chemical properties of SiNSs produced by the deintercalation (removal of a molecule inserted between two others) of calcium dicilicide through a cold aqueous process.

The study used a wide range of techniques including XRD, FTIR, Raman, solid-state NMR, SEM, TEM, EDS, XPS, diffuse reflectance absorbance, steady-state photoluminescence, time-resolved photoluminescence, and thermal decomposition; when they are combined together, these techniques enable unique insight into the structural and optical properties of the Si-NSs.

The paper finds that the results are encouraging for a variety of optoelectronic technologies, such as phosphors, light-emitting diodes, and CMOS-compatible photonics and states that results provide critical structural and optical properties to help guide the research community in integrating Si-NSs into optoelectronic and quantum devices.

In 2018 Panthani received the National Science Foundation CAREER award for research into using optoelectronic properties through nanoscale sheet technology for transmission of data as an alternative to wiring.