Electronic Devi...

Read the following statements regarding semiconductor and mark the incorrect answer.

1. In P type semiconductor, holes as minority charge carrier
2. In N type semiconductor, electron as majority charge carrier.
3. It has conductivity in between the insulator and conductor.
4. At zero absolute temperature, intrinsic semiconductor behaves as a conductor.

The probability that an energy state is filled at E_C + KT, is equal to the probability that a state is empty at E_C + KT. Where is the Fermi level (E_F) located?

Assume that gallium arsenide has dopant concentrations of N_d = 1 × 10¹³ cm^-3 and N_a = 2.5 × 10¹³ cm^-3 at T = 300 K. Assuming that the concentration of donor ‘or’ acceptor is ≫ n_i, the material is

A n-type Si sample is uniformly doped with 10¹⁵ donors per cm³ and has minority carriers lifetime τ_p = 10^-6sec. The photo generation rate that will produce 2 × 10¹³ excess pairs cm^-3 in steady state is _________ × 10¹⁹ eh – pair/sec

A solar cell has a short circuit current of 10 mA and open-circuit voltage of 0.9 V. The maximum power delivered by the solar cell is _________ mW. Given fill factor as 0.8.

The Fermi level in a semiconductor bar should:

If the substrate doping concentration is decreased, the accumulation region capacitance and depletion region capacitance respectively will

Growth of SiO₂ on Si subtrate can be achieved in 2 ways either using oxygen or using water vapour. For growing thicker oxides

Semiconductors have ______ conduction band and ______ valence band.

The Difference between the donor energy level and fermi level in a n-type semiconductor in where 25% of the atoms are ionised at 300 k is:

In an intrinsic semiconductor, the Fermi energy level EF doesn’t lie in the middle of the band gap cause:

A silicon bar is doped with donor impurities ND = 2.25 × 10¹⁵ cm^-3. If the electron mobility μn = 1000 cm2/v-s then the approximate value of resistivity of silicon bar assuming partial ionization of 55% is __________ (Ω - cm)

Consider the uniformly doped GaAs junction at T = 300 K. At zero bias, only 20 percent of the total space charge region is to be in the p region. The built-in potential barrier for an intrinsic concentration of n_i = 1.8 × 10⁶ cm^-3 is V_bi = 1.20 V. The thermal voltage at T = 300 K is 25.9 mV and the relative permittivity ε_r = 13.1, ε₀ = 8.85 × 10^-14 Farad-cm.

A Ga – As LED has refractive index of 3.6 and is surrounded by air (μ = 1). If the bandgap of Ga – As is 1.43. Then out of 500 photons generated in Ga – As, The number of photons emitted out of the specimen are _____

The change in diode voltage that will cause a factor of 50 increase in current for an ideal pn junction diode at T = 300 K operating in the forward-bias region is approximately:

 \((Take\;{V_T} = \frac{{kT}}{q} = 25mV)\) 

A MOSFET with VDS = 0.5 V carries a drain current of 1 mA in saturation. If channel length modulation parameters λ = 0.2 V^-1  then the drain current if VDS is 1 V is:

Holes are injected into n-type Ge so that the at the surface of the semiconductor hole concentration is 10¹⁴/cm³. If diffusion constant of a hole in Ge is 49cm²/sec and minority carrier lifetime is τ_p = 10^-3 sec. Then the hole concentration Δp at a distance of 4mm from the surface is ______10¹⁴/cm³.

The donor impurity must have _______ electrons.

In N-type semi conductor, the majority carriers are______.

N-type semiconductor is obtained by doping silicon with

Consider a uniformly doped silicon bipolar transistor with a metallurgical base width of 0.5 μm and a base doping of N_B = 10¹⁶ cm^-3. The punch-through voltage V_pt is given as V_pt = 25 V with Punch through voltage defined as the base-collector voltage responsible for B-C depletion region to penetrate completely through the base. The collector doping concentration to meet the given punch-through voltage is (up to 2 decimal places) _____________× 10¹⁴ cm^-3.(Take ϵ_r = 11.7)

(Assume bias voltage at collector-base junction is very large as compared to built-in voltage at base-collector region)

An n-type semiconductor can be obtained by doping pure silicon with

What kind of semiconductor is formed when phosphorus is added to silicon?

Why do donor impurities in an n-type semiconductor facilitate electrical conduction compared to an intrinsic semiconductor?

Excess carriers have been generated uniformly in a semiconductor to a concentration of δn(0) = 10¹⁵ cm^-3 (δn(0) represents the excess carrier concentration at t = 0). The forcing function generating the excess carriers turns off at time t = 0. If the excess carrier lifetime is τ_no = 10^-6sec, the excess carrier concentration at t = 10μs is: