Question

Which of the following is an example of an indirect band gap intrinsic semiconductor?
(This question has multiple correct options)
A. Silicon
B. Germanium
C. Gallium Arsenide
D. None of these

Answer 1

The maximal energy of the valence band exists at a particular momentum value to the lowest of the conduction band capacity of an indirect band gap semiconductor.

Complete answer:
The energy gap in a material between electron orbitals wherein the electrons are not free to pass (the valence band) and isotopes in which a current (the conduction band) is comparatively free and can bring.The band gap of the semiconductor may be of two simple kinds. They are:

1. Direct band gap and
2. Indirect band gap.

The substance has an "indirect distance" if the k-vectors appear different. When the crystal momentum for electrons and holes is equal in both the valence band and the conduction band, the band difference is considered direct; an electron will emit a photon directly.

An intrinsic semiconductor indirect band difference is one at which the valence band's maximal energy occurs at a particular k (k-space wave vector) rather than the conduction band's minimum energy. Silicon crystals have less free electrons at room temperature to germanium crystals. This means the silicon would have a much lower current cut off from the collector than germanium.

Hence, the correct options are A and B.

Note: An intrinsic(pure) semiconductor is indeed a pure semiconductor without any noticeable dopant species present, sometimes termed an undoped semiconductor or also i-type semiconductor. Therefore, instead of the quantity of impurities, the quantity of charge carriers is based on the properties of the substance itself.