## What is energy band gap theory?

A band gap is the distance between the valence band of electrons and the conduction band. Essentially, the band gap represents the minimum energy that is required to excite an electron up to a state in the conduction band where it can participate in conduction.

**What is the band theory of semiconductor?**

According to the band theory, semiconductors will actually act as insulators at absolute zero. Above this temperature and yet still staying below the melting point of the solid, the metal would act as a semiconductor. Semiconductors are classified by the fully occupied valence band and unoccupied conduction band.

**What is fundamental band gap?**

The fundamental energy gap is the most basic property of a periodic solid. It cannot be found from a single KS band-structure calculation, even with the unattainable exact density functional.

### How is band gap energy calculated?

By plotting the graph between (ahv)^(1/2) versus photon energy (hv) where, a (alpha) is the absorbance calculated from UV . (hv) can be calculated form wavelength using: (hv = 1240/wavelength);Extrapolating the straight line portion of the curves to zero absorption coefficient value gives the energy band gap value.

**What is the basis of band theory?**

Band theory, in solid-state physics, theoretical model describing the states of electrons, in solid materials, that can have values of energy only within certain specific ranges. The behaviour of an electron in a solid (and hence its energy) is related to the behaviour of all other particles around it.

**What is unit of band gap?**

The energy required for electrons and holes to transition from the valence band to the conduction band is called a band gap. Si (Silicon) has a band gap of 1.12 eV (electron volt). A semiconductor with a large value is called a wide-band-gap semiconductor.

#### What is Fermi level in band theory?

The Fermi Level is the energy level which is occupied by the electron orbital at temperature equals 0 K. The lower energy orbitals combine and form a band called the valence electron band, and the higher energy orbitals combine to form a band called the conduction band.