A Quantum Well is a region of semiconductor material with a narrower bandgap than the surrounding material. This allows electrons and holes to be confined in the well, creating a two-dimensional electron gas (2DEG).

The purpose of a Quantum Well is to create a two-dimensional electron gas (2DEG). This is achieved by confining electrons and holes in the well, creating a region of high electron density.

Quantum Wells have a wide range of applications, including high-electron-mobility transistors (HEMTs), quantum cascade lasers (QCLs), light-emitting diodes (LEDs), and solar cells.

The typical thickness of a Quantum Well is 1-10 nanometers. This is thin enough to confine electrons and holes, but thick enough to prevent them from tunneling out of the well.

The energy difference between the conduction band and the valence band in a Quantum Well is the bandgap. This is the energy required to excite an electron from the valence band to the conduction band.

The bandgap of a Quantum Well decreases with increasing temperature. This is because the thermal energy of the electrons and holes increases with temperature, which makes it easier for them to overcome the bandgap and move from the valence band to the conduction band.

Strain decreases the bandgap of a Quantum Well. This is because strain changes the crystal structure of the semiconductor material, which in turn changes the energy levels of the electrons and holes.

Doping decreases the bandgap of a Quantum Well. This is because doping introduces impurities into the semiconductor material, which change the energy levels of the electrons and holes.

Magnetic field splits the energy levels of a Quantum Well. This is known as the quantum Hall effect.

Electric field splits the energy levels of a Quantum Well. This is known as the quantum Stark effect.

Light splits the energy levels of a Quantum Well. This is known as the quantum confined Stark effect.

Phonons split the energy levels of a Quantum Well. This is known as the phonon-assisted tunneling.

Defects split the energy levels of a Quantum Well. This is because defects introduce impurities into the semiconductor material, which change the energy levels of the electrons and holes.

Disorder splits the energy levels of a Quantum Well. This is because disorder changes the crystal structure of the semiconductor material, which in turn changes the energy levels of the electrons and holes.

Interactions split the energy levels of a Quantum Well. This is because interactions change the energy levels of the electrons and holes.