Upcoming 2DCC Webinars:
Please join us for the Fall 2024 Webinar series.
September 26: RSVP Symposium
Keynote Speaker: Jonathan Chin, Georgia Tech
Title: Impact of substrate and Se concentration on the morphology of MBE-grown SnSe thin films
Abstract: Tin selenide (SnSe) becomes piezoelectric when scaled down near the monolayer limit. The piezoelectric coefficients of SnSe are predicted to exceed those of AlN, but direct measurements have been hindered by the limited ability to achieve oriented SnSe grains of sufficient lateral dimensions to deposit electrodes. To establish control over the thin film orientation and layer count, we employ direct growth of SnSe via molecular beam epitaxy (MBE) at the 2DCC. In this RSVP project, we look at the processing conditions that influence the orientation and morphology of SnSe grains, including substrate selection, Se:Sn flux ratio, and the deposition sequence of Sn and Se. SnSe maintains a (200) orientation when grown on substrates with which it has a lattice mismatch below 5%. Substrates with higher surface energies also show an increase in lateral grain size and film coverage. Additionally, increasing the Se concentration increases the resulting SnSe grain area and promotes layer control. Understanding the influence of processing conditions like substrate selection and flux ratio will help to control the dimensions and morphologies of SnSe thin films deposited by MBE.