Test: Electronic Devices - 2 - Electronics and Communication Engineering (ECE) MCQ

The energy band structure of n-type semiconductor is as shown below

The probability that the donor energy state is empty is (up to 3 significant digits)

In a hypothetical semiconductor hole concentration is 2 × 10¹⁵/cm³ and electron concentration is 1 × 10¹⁵/cm³. The mobility of holes is  and mobility of electrons is  

If the specimen is subjected to hall measurement. Then the measured hall coefficient (R_H) is

In a germanium semiconductor at 127°C has a hole concentration gradient between two points 1.5 × 10²²/m³. If the hole mobility in germanium is 800 cm²/v-s, then the diffusion current density is ______ A/m².

2 Consider two energy levels: E₁, E eV above the Fermi level and E₂, EeV below the Fermi level. P₁ and P₂ are respectively the probabilities of E₁ being occupied by an electron and E₂ being empty. Then

A silicon sample is dope with unknown concentration of Arsenic, such that the fermi level (E_F) is 0.407 eV relative to intrinsic level (E_i). The conductivity of the silicon sample after doping is______(Ω – cm)^-1.

The mobility of electrons μ_n = 3800 cm²/v-s and holes μ_p = 1800 cm²/v-s. Take kT = 0.0259 eV at 300°K and intrinsic concentration n_i = 1.5 × 10¹⁰ cm^-3

The effective density of states in conduction and valence band N_C and N_v at 300K is 4.7x10¹⁷ cm⁻³ and 7x10¹⁸cm⁻³ respectively. The bandgap of the mentioned semiconductor is 1.42eV at 300K. The intrinsic carrier concentration is:

Use Boltzmann constant k = 8.62 x 10⁻⁵ eV/K

Holes are being steadily injected into a region of n-type silicon. In the steady state, the excess hole concentration profile is shown. [The term excess means over and above concentrations p_no]

If  D_p = 12 cm²/sec N_D = 10¹⁶/cm³, n_i = 1.5 × 10¹⁰/cm³ and w = 5 μm.

The current density that will flow in x-direction is _____ nA/cm².