Indian Institute of Science Education and Research Research Fellow Interview Questions, Process, and Tips

2D electron gas refers to a system of electrons confined to move in a two-dimensional plane.

• It is formed when electrons are confined to a thin layer or interface between two materials.

• The electrons in a 2D electron gas exhibit unique quantum mechanical properties.

• It is often studied in the field of condensed matter physics.

• Applications include the development of high-speed transistors and quantum devices.

The dielectric constant is measured by applying an electric field to a material and measuring the resulting polarization.

• Dielectric constant is a measure of a material's ability to store electrical energy in an electric field.

• It is determined by comparing the capacitance of a capacitor with the material as the dielectric to the capacitance of the same capacitor with a vacuum as the dielectric.

• The dielectric constant is...read more

Yes, polychromatic X-ray sources can be used in X-ray diffraction experiments.

• Polychromatic X-ray sources can be used in X-ray diffraction experiments to obtain a wide range of diffraction angles.

• The use of polychromatic X-rays can result in overlapping diffraction peaks, making it difficult to interpret the data.

• Monochromatic X-ray sources are preferred for X-ray diffraction experiments as they provide sharper and mor...read more

Bragg's law relates the angle of incidence of X-rays to the spacing of crystal lattice planes in reciprocal space.

• Bragg's law is used to determine the interatomic spacing in a crystal lattice.

• It states that constructive interference occurs when the path difference between two waves is an integer multiple of the wavelength.

• The law is expressed as nλ = 2d sinθ, where n is an integer, λ is the wavelength of the X-rays, d ...read more

The dielectric constant of a material changes with the frequency of the applied electric field.

• Dielectric constant is a measure of a material's ability to store electrical energy in an electric field.

• The dielectric constant of a material is frequency-dependent because the polarization mechanisms that contribute to it vary with frequency.

• At low frequencies, the dielectric constant is dominated by electronic polarization...read more

The electric field due to an infinitely charged plane is uniform and perpendicular to the plane.

• The electric field is independent of the distance from the plane.

• The electric field lines are parallel and equally spaced.

• The electric field strength is proportional to the surface charge density of the plane.

• The direction of the electric field is perpendicular to the plane.

• The electric field can be calculated using the form...read more

Conductivity in semiconductor materials refers to their ability to conduct electricity.

• Semiconductors have a conductivity between that of conductors and insulators.

• Conductivity can be increased by doping the semiconductor with impurities.

• The conductivity of semiconductors can also be affected by temperature.

• Examples of semiconductor materials include silicon, germanium, and gallium arsenide.