Speaker: Dr. Bivas Saha, Associate Professor, International Centre for Materials Science & Chemistry and 

Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur,.

Title: "Metal/Semiconductor Superlattices: Building Matter Layer-by-Layer"

Date: Thursday, October 23, 2025 - Time: 4 PM

Hi-Tea & Coffee: 5 PM

Venue: CeNSE Seminar Hall 

Abstract:
Since the 1960s, the quest to engineer artificially structured materials has driven efforts 
to combine metals and semiconductors at the nanoscale to unlock novel quantum functionalities. 
Early metal/dielectric multilayers revealed intriguing tunnelling and optical properties but 
lacked atomic-scale interface control. To overcome this, we developed the first epitaxial, 
single-crystalline metal/semiconductor superlattices based on rocksalt nitrides, featuring 
atomically sharp, defect-free interfaces that exhibit hyperbolic optical behaviour and 
unusual thermal transport phenomena.

Building on this foundation, we have now demonstrated a new class of epitaxial 
lattice-matched metal/semiconductor superlattices that transcend conventional structural 
constraints by integrating refractory hexagonal transition metals with wide-bandgap III-nitride semiconductors.
 Exemplified by Hf/AlN superlattices, these systems achieve coherent atomic-layer epitaxy and, 
for the first time, exhibit cross-plane thermionic emission alongside enhanced Seebeck coefficients
 from carrier energy filtering. These advances establish metal/semiconductor superlattices as a 
versatile platform for exploring interface-driven quantum phenomena and developing next-generation 
metamaterials and energy-conversion technologies.

Biography:

Prof. Bivas Saha is an Associate Professor at the International Centre for Materials Science 
and the Chemistry and Physics of Materials Unit, JNCASR, Bangalore. He earned his Ph.D. from 
Purdue University (2014), M.S. from JNCASR (2010), and B.Sc. from Jadavpur University (2007), 
followed by Postdoctoral research at UC Berkeley. His group focuses on epitaxial thin films, 
metal/semiconductor heterostructures, photonics, and topological materials/devices. Prof. Saha 
has published over 80 papers, holds four patents, and has guided multiple graduate students. 
His honours include the DAE BRNS Young Scientist Research Award and the Sheikh Saqr Career Award. 
He also serves as the Editor of Solid State Communications journal.

Host Faculty:  Prof. Pavan Nukala.