Refractive Index and Bandgap Variation in Al<sub>2</sub>O<sub>3</sub>-ZnO Ultrathin Multilayers Prepared by Atomic Layer Deposition
POSTER
Abstract
This research focuses on the study of the refractive index n(λ) and optical bandgap Eg behavior in ultrathin multilayer films of Al2O3-ZnO bilayers grown via atomic layer deposition (ALD) technique on Si(100). The multilayer configuration consists in alternate layers of constant thickness Al2O3 (2 nm) and varying thickness ZnO films in order to obtain a total thickness of ~100 nm. A set of 10 samples based on bilayers with various 2:X thickness ratios were prepared, where X refers to the ZnO layer thickness. X is proportional to the number of cycles (N) of the ZnO precursor, varying from 1 to 100. The total thickness, n(λ) and Eg values of each multilayer sample were studied via spectroscopic ellipsometry. Scanning electron microscope images verified the multilayer total thickness and corroborated the accuracy of the optical model used. We observe that the n(λ) values varies between 1.63 and 2.3 for λ ~ 370 nm and the Eg values decreases when the bilayer thickness increases, with a maximum variation for ΔEg ~1.6 eV. These results reveal that the n(λ) and Eg of this material can be modulated systematically as a function of the bilayer thickness and can been suitable for optoelectronics applications.
*Work supported by PAPIIT and PAPIME projects: IN112117, IN107715 and PE101317.
Presenters
-
Javier Alonso Lopez Medina
- CONACYT - Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México