OPEN DAY AT NATIONAL PHYSICAL LABORATORY

The Department of Electronics & Communication Engineering, Dronacharya College of Engineering, Gurgaon on the occasion of CSIR Foundation Day organized a visit to National Physical Laboratory (NPL), New Delhi on 30th September 2015. Second Year students of ECE department along with faculty coordinator, Mr. Ashish Gambhir, went for the visit.

NPL celebrated 30th September 2015 as OPEN DAY. The organisation gave an opportunity to all educational institutes to visit to their campus. The objective of this visit was to get the students involved in NPL research activity where they got a chance to meet experts of diverse fields, especially in Micro/Nano Electronic related Scientist & Technocrats.

The CSIR- NPL is to strengthen and advance physics-based research and development for the overall development of science and technology in the country. In particular, its objectives are:

1. To establish, maintain and improve continuously by research, for the benefit of the nation, the National Standards of Measurements and to realize the Units, based on the International System

2. To identify and conduct, after due consideration, research in areas of physics which are most appropriate to the needs of the nation and for advancement of the field.

3. To assist industries, national and other agencies in their development tasks by precision measurements, calibration, development of devices, processes and other allied problems related to physics.

Dr. R. P. Aloysius, Senior Scientist, Quantum Phenomena & Applications. explained about “Dilution Refrigerator”. He elaborated to the students that the refrigeration process uses a mixture of two isotopes of helium: helium-3and helium-4. When cooled below approximately 870 millikelvin, the mixture undergoes spontaneous phase separation to form a He-rich phase (the concentrated phase) and a He-poor phase (the dilute phase). At very low temperatures the concentrated phase is essentially pure He, while the dilute phase contains about 6.6% He and 93.4% 4He. The working fluid is He, which is circulated by vacuum pumps at room temperature.

The next visit was in “Molecular Beam Epitaxy (MBE) Lab”. The Scientists of CSIR explained that to make a new crystal using MBE, one has to start off with a base material called a substrate, which could be a familiar semiconductor material such as silicon, germanium, or gallium arsenide. Then fire relatively precise beams of molecules molecules (heated up so they're in gas form) at the substrate from "guns" called effusion cells. “Gun” for each different beam, shooting a different kind of molecule at the substrate, depending on the nature of the crystal you're trying to create. The molecules land on the surface of the substrate, condense, and build up very slowly and systematically in ultra-thin layers, so the complex, single crystal grows one atomic layer at a time. The experts said that is why MBE is an example of what's called thin-film deposition. Since it involves building up materials by manipulating atoms and molecules, it's also a perfect example of nanotechnology.

The visit continued in “Ultrafast Transient Absorption Spectroscopy Lab”. In this lab the Scientist gave a basic description of the ultrafast transient absorption technique, the laser and wavelength-conversion equipment and the transient absorption setup. He discussed the applications of ultrafast transient absorption spectroscopy on systems with increasing degree of complexity, from biomimetic light-harvesting systems to natural light-harvesting antennas.

The further visit was in “Atomic Layer Deposition (ALD) Lab”. In this lab the Scientist told that ALD is a chemical vapor deposition technique where precursor molecules are pulsed into a chamber and react to cover the substrate. The precursor is selected so that it doesn’t react with itself, so that only a monolayer can react with the substrate. A purge gas is introduced to the chamber to remove unreacted precursor. A pulse of oxidant deposits oxygen and removes the precursor ligands, and another purge step is repeated. This series is repeated to build up a film. ALD is known for its ability to produce uniform, conformal films with precise control of thickness. .He further explained to the students about Atomic layer deposition which consists of essentially four steps; 1) metal precursor exposure, 2) evacuation or purging of the precursors and any byproducts from the chamber, 3) exposure of the other reactant species (non-metal precursor), for example nitrogen containing reducing agents for nitrides or reducing agents for metals, and 4) evacuation or purging of the reactants and by product molecules from the chamber and also discussed its various applications.

The students were then shown a 15 min duration film which gave the students an idea about the role of NPL Laboratory and its role to strengthen and advance physics-based research and development for the overall development of science and technology in the country.

This visit provided a valuable opportunity to the students to get involved in knowledge sharing and to think and work on recent research schemes.