DAVIET College

DAVIET has set up Research Centre in January 2008 to promote research in interdisciplinary area of Nanotechnology. It is the first engineering institute in north India to establish a well furnished nanotechnology laboratory. Universal Scanning Probe Microscope (Model NT-MDT Solver PRO M4) was imported from Russia and installed in August 2008. Hind High Vacuum Thin Film coating unit was also installed in the same year.

Other facilities include a Spin Coater (Apex), Solvo thermal, Sol Gel and Co-precipitation Techniques, Electrochemical Cell for growth of Nanowires, Dual Source Meter (Keithley) for I-V Characteristics of fabricated Nano devices.

Achievements: Nano wires of copper (200nm) have been fabricated using electrochemical Cell and Templates synthesis techniques. Hetro-structure of Cu-Se and CdS Nano wires have been grown in the range of 10-200nm. Using chemical synthesis route we have prepared Nano particles and Nano rods Nano Needles of Barium Carbonate, Iron Oxolate, Ba Hexa-ferrites ,Zinc Oxide, Cadmium Oxide and Cadmium Sulphide .Nano particles of Zinc Oxide have been fabricated following Quenching Method with variation in time and temperature. The same composition has been prepared by Hydro Thermal Method also. SEM, TEM, XRD, UV- vis and FTIR characterization have been done for all these samples and reported in International journals of repute. The results of our investigation would certainly be helpful in the fields of Nano electronics, Opto electronics and Material science

Atomic-force microscopy (AFM) or scanning-force microscopy (SFM) is a type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the optical diffraction limit. The information is gathered by “feeling” or “touching” the surface with a mechanical probe. Piezoelectric elements that facilitate tiny but accurate and precise movements on (electronic) command enable very precise scanning. The AFM has three major abilities: force measurement, imaging, and manipulation.

In force measurement, AFMs can be used to measure the forces between the probe and the sample as a function of their mutual separation. This can be applied to perform force spectroscopy.

For imaging, the reaction of the probe to the forces that the sample imposes on it can be used to form an image of the three-dimensional shape (topography) of a sample surface at a high resolution. This is achieved by raster scanning the position of the sample with respect to the tip and recording the height of the probe that corresponds to a constant probe-sample interaction (see section topographic imaging in AFM for more details). The surface topography is commonly displayed as a pseudo-colour plot.

In manipulation, the forces between tip and sample can also be used to change the properties of the sample in a controlled way. Examples of this include atomic manipulation, scanning probe lithography and local stimulation of cells.

Simultaneous with the acquisition of topographical images, other properties of the sample can be measured locally and displayed as an image, often with similarly high resolution. Examples of such properties are mechanical properties like stiffness or adhesion strength and electrical properties such as conductivity or surface potential. In fact, the majority of SPM techniques are extensions of AFM that use this modality.

The AFM has been applied to problems in a wide range of disciplines of the natural sciences, including solid-state physics, semiconductor science and technology, molecular engineering, polymer chemistry and physics, surface chemistry, molecular biology, cell biology and medicine.

Applications in the field of solid state physics include (a) the identification of atoms at a surface, (b) the evaluation of interactions between a specific atom and its neighbouring atoms, and (c) the study of changes in physical properties arising from changes in an atomic arrangement through atomic manipulation.

In cellular biology, AFM can be used to (a) attempt to distinguish cancer cells and normal cells based on a hardness of cells, and (b) to evaluate interactions between a specific cell and its neighbouring cells in a competitive culture system.

Vacuum coating and metalizing is the process of adding a thin film of aluminium or other coating to a material.In principle, the process calls for the evaporation of the coating material inside a vacuum chamber, after which it condenses onto a web of substrate as it passes through.

Paper and film metalizing is utilized in the packaging and decorative market segments. The barrier and decorative markets are noted for their wide variety of products from beer labels to chip bags.

A thickness of less than one micrometer is generally called a thin film while a thickness greater than one micrometer is called a coating. It can be used in:

Electrical conduction: metallic films, transparent conductive oxides (TCO), superconducting films & coatings·        

• Semiconductor devices: semiconductor films, electrically insulating films.
•  Optical films: anti-reflective coatings, optical filters
•  Reflective coatings: mirrors, hot mirrors
• ·Tribological coating: hard coatings, erosion resistant coatings, solid film lubricants
• Energy conservation & generation: low emissivity glass coatings, solar absorbing coatings, mirrors, solar thin film, photovoltaic cells, smart films
•  Magnetic films: magnetic recording
• Diffusion barrier: gas permeation barriers, vapour permeation barriers, solid state diffusion barriers
•  Corrosion protection:
•  Automotive applications: lamp reflectors and trim applications
•  Vinyl record pressing, manufacture of gold and platinum records

Spin coating is a procedure used to deposit uniform thin films to flat substrates. Usually a small amount of coating material is applied on the center of the substrate, which is either spinning at low speed or not spinning at all. The substrate is then rotated at high speed in order to spread the coating material by centrifugal force. A machine used for spin coating is called a spin coater, or simply spinner.

Rotation is continued while the fluid spins off the edges of the substrate, until the desired thickness of the film is achieved. The applied solvent is usually volatile, and simultaneously evaporates. So, the higher the angular speed of spinning, the thinner the film. The thickness of the film also depends on the viscosity and concentration of the solution and the solvent

Spin coating is used for many applications where relatively flat substrates or objects are coated with thin layers of material. The material to be made into the coating must be dissolved or dispersed into a solvent of some kind and this coating solution is then deposited onto the surface and spun-off to leave a uniform layer for subsequent processing stages and ultimate use.

Some technologies that depend heavily on high quality spin coated layers are:

• Photo resist for defining patterns in microcircuit fabrication.
• Dielectric/insulating layers for microcircuit fabrication – polymers, SOG, SiLK, etc.
• Magnetic disk coatings – magnetic particle suspensions, head lubricants, etc.
• Flat screen display coatings. – Antireflection coatings, conductive oxide, etc.
• Compact Disks – DVD, CD ROM, etc.
• Television tube phosphor and antireflection coatings.