Sequential Infiltration Synthesis for Nanopatterning
In this project, we develop fabrication process of oxides and nitride materials nanostructures pattern by utilizing a method called Sequential Infiltration Synthesis (SIS); and investigate the growth mechanism and optical properties of the fabricated nanorods. SIS is a localized vapor deposition process using polymers for achieving large-scale uniformity of organized nanoscale materials. SIS has been explored extensively by several research groups and by industry leaders in the last few years including PI Biswas. The SIS method potentially can be used for other materials and other nanostructure morphologies to be integrated in emerging devices in the future.
Fabricated inorganic nanostructure patterns using polymer as template and SIS method
Fourier Transform Infrared Spectroscopy to study Sequential Infiltration Synthesis (SIS)In this work sequential infiltration synthesis (SIS) a modified atomic layer deposition method in polymeric materials are studied using in situ Fourier transform infrared (FTIR) spectroscopy. We study in situ Fourier transform infrared (FTIR) spectroscopy during Al2O3 and TiO2 SIS in different polymers to understand the reaction dynamics between these polymers and the Al2O3 and TiO2 precursors. The goal is to provide insight into the variety of mechanisms involved in polymer-inorganic precursor interactions during BCP lithography, which is currently an expanding nanopatterning technology. Understanding the reaction dynamics between these polymer-metal precursor pairs for superior, inexpensive and large-scale inorganic oxide synthesis is essential. In collaboration with Argonne National Laboratory we are trying to understand these mechanism.
In situ FTIR to understand the reaction dynamics
Oxide NanopatternsInorganic oxides such as TiO2 and ZnO are highly promising semiconductor material for various applications such as photo catalysis, water splitting, solar cells, super capacitors and lithium-ion batteries. In this project we explore the nanostructures fabrication of three commonly used oxides in optoelectronics applications TiO2, Al2O3 and ZnO using BCP as a template. Recently we demonstrated TiO2 nanodots of sub-50 nm dimension using BCP cylindrical nanostructures as template. PLD which is commonly used as a thin film deposition technique is used as inorganic oxide deposition method. In this approach, the PLD at room temperature and in a vacuum has been used. Since combining self-assembled BCP template in inorganic nanostructure fabrication requires a low-temperature (approximately 100°C or less) inorganic deposition process to avoid polymer degradation, in this work, we have used room temperature PLD method to deposit TiO2. Other oxide deposition method we use are chemical solution deposition and atomic layer deposition (ALD). We characterize the BCP and oxide nanostructures using scanning electron microscopy (SEM) and atomic force microscopy (AFM) images, X-ray photoelectron spectroscopy (XPS), Xray diffraction (XRD), and photoluminescence (PL) spectroscopy. We are continuously working on improving overall morphological shape and quality of different oxides.
Block Copolymer Templated Fabrication of TiO2 Nanodot Films Using Pulsed Laser Deposition, K Pandey, K Ghosh, U Manna, M BiswasThe Journal of Physical Chemistry C 122 (28), 16325-16332 (2018)
Schematic of the Fabrication Process
Si Nanoparticles SynthesisIn this ongoing project, we are fabricating colloidal spherical Silicon nanoparticles of 50-250 nm in size for optical applications. We are collaborating with Dr. Uttam Manna at ISU and Dr. Norbert Scherer at the University of Chicago to study the optical characteristics of these nanoparticles.
Anric ALD System
Inert Atmosphere Glove Box
High Temperature (1700 oC) Furnace
Clean bench for sample preparation
Field Emission Scanning Electron Microscope (Zeiss Sigma 300)
Cathodoluminescence Imaging (Zeiss )
Energy Dispersive X-ray Spectroscopy (EDS) (Oxford Instrument)
Fourier Transform Infrared Spectroscopy at Biswas lab, ISU
Photoluminescence Spectroscopy at Manna Lab, ISU