Osm Physics by Ashish

  Thermal evaporation is a common Physical Vapor Deposition (PVD) technique used to create thin films of material on a substrate . The process involves heating a solid source material within a high-vacuum chamber until it vaporizes; these vaporized atoms or molecules then travel in a straight line to a cooler substrate, where they condense to form a thin, uniform coating.  Core Mechanism The process relies on three critical components to ensure high-quality film deposition:  High Vacuum Environment: Typically conducted at pressures below 10^{-5}Torr. This provides a "mean free path"—the average distance a particle travels before colliding with another—that is longer than the distance between the source and the substrate, ensuring atoms arrive unscattered. Heating Source: The material is heated until its vapor pressure becomes significant. Condensation: The vapor reaches the substrate (e.g., a silicon wafer or glass slide) and transitions back into a solid state, buil...

 Nanostructured materials (with dimensions typically in the 1–100 nm range) can be synthesized using a wide variety of physical and chemical methods . Each approach differs in terms of cost, scalability, control over size/shape, and application suitability. 1. Physical Methods of Nanostructured Materials Physical methods generally involve top-down approaches , where bulk materials are broken down into nanoscale structures. (a) Mechanical Milling (Ball Milling) Bulk material is ground into nanoparticles using high-energy balls. Advantages: Simple, cost-effective, scalable. Disadvantages: Contamination, poor control over shape and size. (b) Physical Vapor Deposition (PVD) Material is vaporized and deposited on a substrate in vacuum. Techniques include: Thermal evaporation Sputtering Applications: Thin films, coatings, electronics. (c) Laser Ablation High-energy laser pulses strike a target material to produce nanoparticles. Advantages: High purity, no chemical contamination. Dis...

-Spectroscopy Lab  To study the diffraction pattern of LASER light using single slit.  Verification of Cauchy's Dispersion relation.  Determine the Planck constant using a solar Cell.  Determination of the velocity of Ultrasonic waves.  To determine the wavelength of He-Ne Laser.  To find the Bohr Magneton by Zeeman Effect Experiment.

 . Nanotechnology-II Unit-I Nanoscale Properties–I: Magnetism: Magnetic Moment in clustersor Nanoparticles, Magnetic Order, coercivity, Magnetocrystalline Anisotropy, thermal activation and Superparamagneticeffects. Electronics and Optoelectronics: Ǫuantum Confinement of Super lattices and Ǫuantum Wells, Doping of a Nanoparticle, Excitonic Binding and Recombination Energies, Capacitance in a Nanoparticle. Unit-II Nanoscale properties – Il: Diffusion in Nanocrystalline Materials: Diffusion In Grain Boundaries Of Metals, Nanocrystalline Ceramics, Correlation Between Diffusion and Crystallite Growth, Other properties: brief overview of optical properties, mechanical properties including superplasticity phenomena, reactivity of nanoparticles. Unit-III Characterization Methods: X-ray diffraction: Debye-Scherer formula, dislocation density, micro strain. Synchrotron Radiation: Principle and Applications. Dynamic Light Scattering (DLS), Electron microscopes: Scanning Electron Microscope (...

 Syllabus :  Generic Methodologies for Nanotechnology: Introduction and classification, What is nanotechnology? Classification of nanostructures: Nanoscale architecture; The free electron model and energy bands, Crystalline solids, Periodicity of crystal lattices, Electronic conduction ; Effects of the nanometer length scale , Changes to the system total energy, Changes to the system structure , How nanoscale dimensions affect properties. 1. Introduction to Nanotechnology Nanotechnology is the branch of science and engineering that deals with the study, design, synthesis, characterization, and application of materials and devices at the nanometer scale . The word nano is derived from the Greek word nanos , meaning dwarf . In measurement, 1 nanometer (nm) = 10⁻⁹ meters Nanotechnology focuses on materials whose size ranges from 1 nm to 100 nm . At this scale, materials exhibit unique physical, chemical, electrical, mechanical, and optical properties that differ significantly ...

. B.Sc. VI Semester (Physics Lab) 1.       Determination of Planck's constant by photo cell (retarding potential method using optical filters, preferably five wavelengths). 2.       Determination of Planck's constant using solar cell. 3.       Determination of Stefan's constant (Black body method). 4.       Study of the temperature dependence of resistivity of a semiconductor using four probe-methods. 5.       Study of Iodine spectrum with the help of grating and spectrometer and ordinary bulb light. 6.       Study of characteristics of a GM counter and verification of inverse square law for the same strength of a radioactive source. 7.       Study of β-absorption in Al foil using GM Counter to find endpoint energy. 8.       To find the magnetic susceptibility of a paramagnetic solution usi...

 . B.Sc. V Semester (Physics Lab) 1.       Verify Kirchhoff's laws using breadboard circuits with resistors and voltage sources. 2.       Verify the maximum power transfer theorem. 3.       Study the characteristics of a given transistor (PNP/NPN) in common emitter, common base, and common collector configurations. 4.         Determine the band gap of a semiconductor using a junction diode. 5.        Study the variation of gain with frequency in a single-stage transistor audio amplifier. 6.         Study the temperature dependence of resistance in a semiconductor using the four-probe method. 7.       Study the characteristics of a junction diode and a Zener diode. 8.       Study the characteristics of a field effect transistor (FET) and design an amplifier with finite ga...

 . B.Sc. IV Semester (Physics Lab) 1.       To study the Faradays Law of electromagnetic induction. 2.       To study the variation of power transfer by two different loads by a D.C. source and to verify the maximum power transfer theorem. 3.       To study the variation of charge and current in an RC circuit with a different time constant (using a DC source). 4.       To study the behaviour of an RC circuit with varying resistance and capacitance using AC mains as a power source and also to determine the impedance and phase relations. 5.       To study the rise and decay of current in an LR circuit with a source of constant emf. 6.       To study the voltage and current behaviour of an LR circuit with an AC power source. Also determine power factor, impedance and phase relations. 7.       To study the magneti...

 . B.Sc. III Semester (Physics Lab) 1. Study the variation of the time period with amplitude in large-angle oscillations using a compound pendulum. 2. To study the damping using a coupled pendulum. 3. To study the excitation of normal modes and measure frequency splitting into two coupled oscillators. 4. To study the frequency of energy transfer as a function of coupling with mass using coupled oscillators. 5. To study the viscous fluid damping of a compound pendulum and determiner the damping coefficient and quality factor of the oscillator. 6. To study the electromagnetic damping of a compound pendulum and to find the variation of damping coefficients with the assistance of a conducting lamina. 7. Study of normal modes of a coupled pendulum system. Study of oscillations in mixed modes and find the period of energy exchange between the two oscillators. 8. To determine Young's modulus by bending of the beam method. 9. To determine Y, σ and η by Searle's meth...

Nanostructure Synthesis Methods Suitability for Scaling and Potential Uses of Nanostructure Synthesis Methods 1. Precipitation Method Suitability for Scaling Highly suitable for large-scale production Simple chemical reactions in solution Low-cost equipment required Operates at room or moderate temperatures Can be adapted to continuous industrial processes Requires control over pH, temperature, and concentration Potential Uses Metal oxide nanoparticles (ZnO, TiO₂, Fe₂O₃) Catalysts Pigments and coatings Environmental remediation Low-cost gas sensors 2. Reactive Method Suitability for Scaling Industrially scalable Suitable for mass production Requires high-temperature furnaces Long reaction times and high energy consumption Limited control over nanoscale morphology Potential Uses Ceramics and advanced materials Battery materials Bulk catalysts Magnet...

Hydrothermal and Solvothermal Methods Hydrothermal / Solvothermal Methods for Nanostructure Synthesis 1. Introduction Hydrothermal and solvothermal methods are solution-based synthesis techniques performed in a sealed autoclave at elevated temperature and pressure. These methods enable the formation of highly crystalline nanostructures with controlled morphology. Hydrothermal method: Water is used as solvent Solvothermal method: Organic solvents are used 2. Principle At high temperature and pressure, the solubility of precursors increases, which enhances reaction kinetics and allows controlled nucleation and crystal growth of nanostructures. 3. Mechanism Step 1: Dissolution Precursors dissolve in the solvent forming reactive species. Step 2: Supersaturation Supersaturation leads to nucleation. Step 3: Nucleation Formation of stable nuclei occurs. Step 4: Growth Crystal growth takes place via diffusion and surface reactio...

Reactive Methods for Synthesis of Nanostructures Reactive Methods for the Synthesis of Nanostructures 1. Introduction Reactive methods involve the formation of nanostructures through controlled chemical reactions such as reduction, oxidation, hydrolysis, condensation, and decomposition. These methods allow precise control over particle size, morphology, and composition. 2. Fundamental Mechanism (i) Generation of Reactive Species M n+ → M 0 (reduction) M(OR) n + H 2 O → M(OH) n (ii) Nucleation Formation of stable nuclei under supersaturation conditions. (iii) Growth Controlled by diffusion or surface reaction mechanisms. (iv) Stabilization Surfactants prevent agglomeration and control particle size. 3. Types of Reactive Methods 3.1 Sol–Gel Method Principle Transformation of a sol into a gel through hydrolysis and condensation. Reactions Hydrolysis: M(OR) n + H 2 O → M(OH) n + ROH Condensation: M–OH + M–OH → M–O–M + H 2 O S...

Precipitation Method (Co-precipitation) Precipitation Method (Co-precipitation Method) 1. Introduction The precipitation (co-precipitation) method is a widely used wet chemical technique for synthesizing nanostructured materials such as metal oxides, hydroxides, and composites. It involves the formation of an insoluble solid (precipitate) when soluble precursors react in solution. 2. Basic Principle The method is based on supersaturation, leading to nucleation and growth of nanoparticles. Chemical Reaction: M n+ + X m- → MX ↓ Example: Fe 3+ + 3OH - → Fe(OH) 3 ↓ 3. Mechanism of Formation (i) Supersaturation Occurs when ion concentration exceeds solubility Drives nucleation (ii) Nucleation Formation of small stable nuclei Can be homogeneous or heterogeneous (iii) Growth Controlled by diffusion and surface reactions (iv) Ostwald Ripening Smaller particles dissolve and redeposit on larger ones 4. Co-pr...