0
What else can I help you with?
Why conduction band and valence band partially filled?
No. Conduction band is basically the unfilled energy levels into which electrons can be excited to provide conductivity.
Do semiconductor material have a very high resistance at room temperature?
No. As temperature increases, resistance of semiconductors decrease. This is because semiconductors have a small energy gap between their valence band and conduction band (in the order of 1 eV). Electrons must exist in the conduction band in order for the material to conduct but electrons exist in the valence band naturally. The electrons gain thermal energy for surroundings and jumps the energy gap from valence band to conduction band and hence, the SC material more readily conducts. As temperature increases, electrons can gain more thermal energy, more electrons can enter the conduction band and hence, resistance decreases.
What is the difference between the resistance of conductor and insulator?
Conductors allow most, if not all, electricity to pass through it. This is due to "wandering electrons" that aren't tightly bound to the nucleus of the conductor itself.Resistors conduct some, but not all electricity to pass. It somewhat resists it, hence resistors.Insulators do not allow electricity to pass through it due to the electrons being so tightly bound to the nucleus.
If a pure Si crystal has a million free electrons inside it how many holes does it have.what happens to the no of free electrons and holes if the ambient temperature increases?
If the crystal is pure Si (no dopants or impurities) then the number of free electrons in the conduction band will be equal to the number of holes in the valence band. Each electron leaves behind a hole when it is thermally excited into the conduction band. If the ambient temp. increases, there will be more thermal energy available which will increase both the number electrons and the number of holes.
Why is plastic a bad conductor of electricity?
Generally, the valence electrons in the atoms of the molecules in plastic hang out in Fermi energy levels lower than the energy bands that an electron would have to occupy to support conduction. The electrons are bound to parent atoms, and they also may have some mobility within the molecular matrix of the material, but any energy applied (like voltage) doesn't really get the attention of these electrons. They chill in energy levels too low to be jerked up into the conduction band with any fair amount of applied voltage. And if the electrons are not in or cannot easily reach the conduction band (an energy level high enough to support current flow), the material won't support conduction and is said to be a bad conductor.
What is the relationship between the valence and conduction bands in semiconductor materials?
In semiconductor materials, the valence band is the highest energy band occupied by electrons, while the conduction band is the next higher energy band that electrons can move into to conduct electricity. The energy gap between the valence and conduction bands determines the conductivity of the semiconductor.
What is the difference between the valence band and the conduction band in a material's electronic structure?
The valence band is the energy band in a material where electrons are normally found, while the conduction band is the energy band where electrons can move freely to conduct electricity. The key difference is that electrons in the valence band are tightly bound to atoms, while electrons in the conduction band are free to move and carry electric current.
What is valence band?
It is the band of energy of an electron in outer most orbit
Why conduction band and valence band partially filled?
No. Conduction band is basically the unfilled energy levels into which electrons can be excited to provide conductivity.
Do semiconductor material have a very high resistance at room temperature?
No. As temperature increases, resistance of semiconductors decrease. This is because semiconductors have a small energy gap between their valence band and conduction band (in the order of 1 eV). Electrons must exist in the conduction band in order for the material to conduct but electrons exist in the valence band naturally. The electrons gain thermal energy for surroundings and jumps the energy gap from valence band to conduction band and hence, the SC material more readily conducts. As temperature increases, electrons can gain more thermal energy, more electrons can enter the conduction band and hence, resistance decreases.
Why in intrinsic semiconductors do you need to apply very high potential to transfer electrons from the valence band to the conduction band?
Semiconductors, in the absence of applied electric fields, act a lot like insulators. In these materials, the conduction band and the valence band do not overlap. That's why they insulate. And that's why you have to apply some serious voltage to them to shove the valence electrons across the gap between the valence and conduction bands of these semiconductor materials. Remember that in insulators, there is a "band gap" between the lowest Fermi energy level necessary to support conduction and the highest Fermi energy level of the valence electrons. Same with the semi's. In metals, the conduction band overlaps the valence band Fermi energy levels. Zap! Conductivity.
What is the name of two energy bands at which current is produced in silicon?
The two energy bands in which current is produced in silicon are the valence band and the conduction band. Electrons in the valence band can be excited to the conduction band by absorbing energy, allowing them to move and create an electric current.
How many valence electrons does insulator have?
It is not the number of valence electrons that an insulator has that is important. It is the way the valence electrons are "arranged" in the structure of the material that matters. If not all the valence electrons of a substance are "involved" in the structure of the material, then these electrons are said to be free electrons. They move about in the substance, and are free to contribute to electron flow. The metals are examples. In contrast with this, if all the electrons are bound up in a material, they are not free to support current flow, and the material is said to be an insulator. Said another way, if the valence electrons in a material are in a Fermi energy level that overlaps the conduction band for that material, the material is a conductor. In an insulator, the valence electrons are all in Fermi energy levels that are below the conduction band for that material, and it is an insulator. Applying a voltage to an insulator will not "lift" the valence electrons up into the conduction band to allow them to support current flow.
How does the energy of the core electrons compare with the energy of valence electrons?
The energy of the valence electrons is greater than the energy of the core electrons.
What is the difference between the band structure of a semiconductor and that of a metal?
In a semiconductor, the band structure has a small energy gap between the valence and conduction bands, allowing for some electrons to move from the valence band to the conduction band when excited. In a metal, there is no energy gap between the bands, allowing electrons to move freely throughout the material.
Why does a semiconductors ability to conduct electricity increase when temperature rises?
if we increase the temp so large no of electrons jumbs from valence energy band to conduction energy band .when there are alarge no of electrons in conduction band to the conduction increase means this simiconductor can conduct easyly. thanx Engr Bashir Khan.
How does the energy of core electrons compare with the energy of valence electrons?
The energy of the valence electrons is greater than the energy of the core electrons.
