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Which type of band gap does GaAs have?
Gallium Arsenide (GaAs) has a 2.5eV band gap (@ 295 K)
Is ZnSe is direct or indirect band gap?
It is direct band gap material.
Titanium dioxide is direct band gap or indirect band gap material?
Yes it is. Most Sn (tin) materials as semiconductors are direct band gap materials. Silicon on the other hand is an indirect band gap material.
Is silicon a direct band gap material?
Silicon is by all means an indirect band gap material.
The gallium arsenide is prepared for laser action but silicon and germanium are not. explain why?
I think because GaAs has a direct band gap transition but Si and Ge has indirect band gap transition. Both silicon and germanium are opaque and thus cannot be used to make LASERs.
Why direct band gap semiconductor is used in light emitting diode?
Direct band gap semiconductors are used in light-emitting diodes (LEDs) because they allow for efficient photon emission when electrons recombine with holes. In these materials, the transition from the conduction band to the valence band occurs at the same momentum, enabling the direct release of energy in the form of light. This efficiency in light production is crucial for applications in displays and lighting. Examples of direct band gap semiconductors include gallium arsenide (GaAs) and indium gallium nitride (InGaN).
Why indirect band gap material is used for manufacturing LED's?
Optical sources like LEDs use direct band gap so that conduction band electorn can recombine directly with a hole in valence band .
What are the difference between direct and indirect band gap materials?
In a direct band gap the electron only needs energy to jump to the conduction band. In an indirect band an electron needs energy and momentum to jump to the conduction band
Why silicon is a indirect band gap material?
Silicon is considered an indirect band gap material because the maximum of its valence band and the minimum of its conduction band occur at different momentum values (k-values) in its crystal structure. This means that a direct transition of electrons from the valence band to the conduction band requires a change in momentum, which is not possible without the assistance of a phonon (a quantized mode of vibration). As a result, silicon is less efficient at absorbing and emitting light compared to direct band gap materials, which have their band extrema aligned in momentum space. This property is crucial for its applications in electronic devices rather than optoelectronic applications.
Give some Examples of direct and indirect band gap semiconductors?
direct band gap-semiconductor in which the bottom of the conduction band and the top of the valence band occur at the momentum k=0;in the case of d.b.s. energy released during band-to-band electron recombination with a hole is converted primarily into radiation (radiant recombination); wavelength of emitted radiation is determined by the energy gap of semiconductor; examples of d.b.s. GaAs, InP, ZnS, ZnSs, CdS, CdSe etc. indirect bandgap semiconductor --semiconductor in which bottom of the conduction band does not occur at effective momentum k=0, i.e. is shifted with respect to the top of the valence band which occurs at k=0; energy released during electron recombination with a hole is converted primarily into phonon; e.g. Si, Ge, GaP, GaAsp ,Ge etc, .
What are the Characteristics of Direct and indirect band gap semiconductors?
Direct band semconductors are mostly for LEDs. Indirect band semiconductors like Si and Ge are conventional diodes.
What is the difference between direct and indirect energy?
The band gap represents the minimum energy difference between the top of the valence band and the bottom of the conduction band, However, the top of the valence band and the bottom of the conduction band are not generally at the same value of the electron momentum. 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.In an indirect band gap semiconductor, the maximum energy of the valence band occurs at a different value of momentum to the minimum in the conduction band energy
