Magic Sized Islands on Layered Materials

Dr. Andrew Stollenwerk

University of Northern Iowa

 

Abstract

The energy associated with quantum well states was found to play a critical role in determining the geometric structure of Au(Ill) and Ag(111) islands grown on the surface of MoS2. Under this growth mode, the wave nature of electrons causes the total energy to oscillate with island dimensions. Island stability increases as quantum states shift farther from the Fermi level, lowering the energy of the island. The preferred dimensions observed in Au and Ag on MoS2 have relatively large periodicities and persist to higher temperatures than have been observed in previous systems exhibiiting quantum growth modes. This is likely due to the weak van der Waals interface, which can induce epitaxial growth with minimal stress in the absence of a wetting layer or significant lattice matching, The abrupt van der Waal gap at the interface also gives rise to strong elctronic confinement, ideal for the formation of quantum well states. These findings indicate the potential to explore electronic growth modes in a new clas of systems based on metal-layered semiconductor interfaces.

 

Speaker Biography

Dr. Stollenwerk received a B.S. in physics and a B.A. in mathematics at Miami University in 2002. His graduate work was performed at the University at Albany SUNY, where he received his M.S. in physics in 2004 and his Ph.D. in Nanoscience in 2007. He joined the physics department at the University of Northern Iowa in 2009 after a two year postdoctoral fellowship at Harvard University in the field of applied physics.