Abstract
The ability to control surface and interface properties at the atomic and molecular levels has become a central challenge in modern materials science. While defects have traditionally been viewed as undesirable imperfections that degrade device performance, recent advances demonstrate that carefully engineered surface states can provide unique opportunities to tailor optical, electronic, and chemical functionality. In this seminar, I will present our recent efforts in understanding and exploiting surfacecontrolled phenomena in semiconductors and nanostructured materials. The discussion will focus on the functionalization of silicon, GaN, plasmonic nanostructures, and emerging optoelectronic platforms, where molecular surface chemistry and nanoscale engineering are combined to manipulate charge transfer, surface doping, band bending, optical absorption, and carrier dynamics. The surface chemistry, molecular kinetics, stability and coverage of molecules will be discussed. Advanced surface-sensitive techniques, including Kelvin probe spectroscopy, surface photovoltage measurements, Raman spectroscopy, x-ray photoelectron spectroscopy, provide fundamental insight into the molecular-surface interaction. I will further demonstrate how engineered defects and chemically tailored interfaces can enable new generations of devices such as Field effect transistors, renewableenergy devices, and intelligent systems.