## Intrinsic material, Electrical Engineering

Assignment Help:

Intrinsic Material

1. A perfect semiconductor crystal with no impurities or lattice defects.
2. No carriers at 0 K, since the valence band is completely full and the conduction band is completely empty.
3. For T > 0 K, electrons are thermally excited from the valence band to the conduction band (EHP generation).
4. EHP generation takes place due to breaking of covalent bonds => required energy = Eg.
5. The excited electron becomes free and leaves behind an empty state (hole).
6. Since these carriers are created in pairs, the electron concentration (n/cm3) is always equal to the hole concentration (p/cm3), and each of these is commonly referred to as the intrinsic carrier concentration (ni).
7. Thus, for intrinsic material n = p = ni.
8. These carriers are not localized in the lattice; instead they spread out over several lattice spacings, and are given by quantum mechanical probability distributions.
9. Note: ni = f (T).
10. To maintain a steady-state carrier concentration, the carriers must also recombine at the same rate at which they are generated.
11. Recombination occurs when an electron from the conduction band makes a transition (direct or indirect) to an empty state in the valence band, thus annihilating the pair.
12. At equilibrium, ri =gi, where gi and ri are the generation and recombination rates respectively, and both of these are temperature dependent.
13. gi(T) increases with temperature, and a new carrier concentration ni is established, such that the higher recombination rate ri(T) just balances generation.
14. At any temperature, the rate of recombination is proportional to the equilibrium concentration of electrons and holes, and can be given by ri= αrn0p0 = αrni2=gi(5) where αris a constant of proportionality (depends on the mechanism by which recombination takes place).

#### Explain the operation of interrupt return instruction, Explain the operatio...

Explain the operation of IRET instruction.  What memory locations contain the vector for an INT 34 instruction? The Interrupt return (IRET) instruction is utilized only along w

#### Determine the dielectric constant of slab, Determine the Dielectric constan...

Determine the Dielectric constant of slab: An air capacitor contains two parallel plates 10 cm 2 in area and 0.5 cm apart. While a dielectric slab of area 10 cm2 and thicknes

#### Describe transistor stability parameters, Q. Describe transistor stability ...

Q. Describe transistor stability parameters The two parameters are · The stability factor ,K · Stability measure,ß1 These parameters determine the transistor stability

#### Input voltage to system and the output motor speed, A system contains an am...

A system contains an amplifier with a gain of 10 offering the armature voltage for a motor which provides an output speed which is proportional to the armature voltage, the constan

#### The internal resistance of the zener diode, A 9.1V zener diode has a nomina...

A 9.1V zener diode has a nominal voltage fall at a test current of 28mA. The internal resistance of the zener diode is 5 ohms. Find the voltage drop across the zener diode at zener

#### Find the output function y for the logic circuits, Q. Find the output funct...

Q. Find the output function Y for the logic circuits of Figure (a) and (b). An AOI (AND-OR-INVERT) gate is shown in Figure with its two possible realizations. Obtain the output

#### permanent magnet stepper motor - stepper motor , Normal 0 fa...

Normal 0 false false false EN-IN X-NONE X-NONE   Permanent   Magnet Stepper Motor The s

#### Working of r digital to analog converter, 2 n -R D/A CONVERTER An n-bit...

2 n -R D/A CONVERTER An n-bit 2 n -R D/A converter needs 2 n resistors of equal value R and (2 n+1 -2) analog switches. A 3-bit 2 n -R D/A converter is shown in Figure, which

#### Projects, I want project ideas.

I want project ideas.

#### Electro Chemistry, Construction and working of calomel electrode

Construction and working of calomel electrode

### Write Your Message!  #### Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!