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Why is silicon not used in fabrication of LED?
Silicon is an indirect band gap semiconductor
Is silicon a direct band gap material?
Silicon is by all means an indirect band gap material.
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, .
Are free electron in valence band or conduction band?
In semiconductors free electrons are in conduction bands.
What are valence band?
The quantum mechanical energy band where electrons reside in semiconductors that participate in interatomic bonding.
Why do we mostly use indirect semiconductors?
The indirect band gap semiconductors like silicon and germanium are mostly used because they are elemental, plentiful, and easier to process than the direct band gap semiconductors which are alloys or compounds.
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 ZnSe is direct or indirect band gap?
It is direct band gap material.
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
What is direct semiconductor?
A direct semiconductor is a type of semiconductor material in which the maximum of the valence band and the minimum of the conduction band occur at the same momentum value in the Brillouin zone. This alignment allows for efficient absorption and emission of light, making direct semiconductors ideal for optoelectronic applications such as light-emitting diodes (LEDs) and laser diodes. Common examples include gallium arsenide (GaAs) and indium phosphide (InP). In contrast, indirect semiconductors require a change in momentum for electron transitions, which makes them less efficient for light-related applications.
Do compound semiconductors behave as intrinsic semiconductors?
No, compound semiconductors do not behave as intrinsic semiconductors because they have different band structures due to the combination of different elements. Compound semiconductors have unique electrical properties that make them suitable for specific applications that require different performance characteristics compared to intrinsic semiconductors.
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 is silicon not used in fabrication of LED?
Silicon is an indirect band gap semiconductor
Is silicon a direct band gap material?
Silicon is by all means an indirect band gap material.
Why is LED not made of silicon or germanium?
Silicon and Germanium are not used to make LEDs.They are opaque to visible lightThey have the wrong type of band gap (direct instead of indirect).LEDs are made with binary semiconductors, like:Indium Gallium NitrideSilicon CarbideIndium PhosphideGallium Indium Arsenide NitrideIndium Gallium Aluminum Phosphideetc.
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 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
