Oral: Optical Properties of Thin Film Silver Iodide

Silver iodide (AgI) is a non-centrosymmetric, wide-bandgap semiconductor, and may enable nonlinear optical functionalities at ultraviolet wavelength regime. Thin AgI platelets with a 10-100nm thickness range were successfully grown by physical vapor deposition, confirmed by x-ray diffraction, Raman effect, and atomic force microscopy. Interestingly, strong second harmonic generation and two-photon photoluminescence (2PPL) from excitons have been observed from those thin platelets. The 2PPL suggests exciton transition energies of approximately 2.79 eV or 2.98 eV, depending on the growth conditions. We will discuss the structure-property relationship of these observations.