What is direct band gap in semiconductor?

What is direct band gap in semiconductor?

A direct band-gap (DBG) semiconductor is one in which the maximum energy level of the valence band aligns with the minimum energy level of the conduction band with respect to momentum.

What is direct and indirect energy band gap semiconductor?

In a direct band gap semiconductor, the top of the valence band and the bottom of the conduction band occur at the same value of momentum, as in the schematic below. In an indirect band gap semiconductor, the maximum energy of the valence band occurs at a different value of momentum to the.

Is an example of direct band gap semiconductors?

Examples for direct band gap semiconductor materials are gallium arsenide (GaAs), indium gallium arsenide (InGaAs), gallium nitride (GaN), aluminum nitride (AlN), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium tellurite (CdTe), zinc sulfide (ZnS), lead sulfide (PbS) and lead selenide (PbSe).

What is direct and indirect transition?

Direct or indirect transition are ”allowed” transitions, if the momentum matrix element charaterizing the transition is different from zero. This means that the transition can hold for sure if sufficient energy is given to the particle (e.g. electron) involved in the process.

Is silicon a direct band gap semiconductor?

It is well known that Si is an indirect band gap semiconductor with a large energy difference between the direct gap (3.5 eV) and the indirect gap (1.1 eV).

Is germanium direct band gap?

Abstract. Germanium (Ge) is a group-IV indirect band gap semiconductor but the difference between its direct and indirect band gap is only 140 meV. It has been shown that when Ge is subjected to a tensile strain and a heavy n-doping level, room-temperature photoluminescence (PL) can be greatly enhanced.

What are direct semiconductors?

Direct bandgap semiconductors are used in light-emitting applications like LED and LASER. Ex. GaAs, CdS, ZnS, CdSe etc. Indirect Band Gap semiconductor – In Indirect bandgap semiconductor, top of the valence band and bottom of the conduction band lies at different values of K.

Is silicon direct or indirect band gap?

What is the band gap of silicon?

1.12 eV
Si (Silicon) has a band gap of 1.12 eV (electron volt).