Draw the profile of electron and hole density as a function of energy for (i) When Ef is 3kT above the conduction band and (ii) When Ef is 3kT below the valence band at room temperature.
Draw the profile of electron and hole density as a function of energy for (i) When...
(0)If in GaAs, the Fermi level is 0.30 eV below the conduction band. [10] calculate the thermal equilibrium electron and hole concentration at room temperature. Bandgap of CaAs is 1.42 eV, the effective density of states of the conduction band at 300K is 4.7x10 cm and the effective density of states of the valence band is 7x10¹ cm³.L213(11)Identify and illustrate with required equations and diagrams, how energy and momentum are conserved in band to band transitions in indirect band gap...
(2) In a semiconductor with an energy gap Eg between the valence and the conduction bands we can take Ef (the Fermi energy) to be halfway between the bands (see figure below): Conduction band Energy gap Eg Valence band Semiconductor a. Show that for a typical semiconductor or insulator at room temperature the Fermi- Dirac factor is approximately equal to exp(-E 2kBT). (Typical Eg for semi-conductors ranges from about 0.5eV to 6eV at T-293K.) b. In heavily doped n-type silicon,...
In a semiconductor it can be shown that the product of the electron and hole densities is the square of the intrinsic density, i.e., pm n. Find the equilibrium electron (n) and hole (p) concentrations and the location of the Fermi level (EF) referenced to the conduction band (Ec) or valence band (Ev) in Si at 27°C if the Si contains the following concentrations of shallow dopant atoms: a) 1x1016 cm-3 boron atoms b) 3x1016 cm-3 arsenic atoms and 2.9x1016...
a) Show that the chemical potential in an intrinsic semiconductor lies in the middle of the gap at low temperature. (b) Explain how the chemical potential varies with temperature if the semiconductor is doped with (i) donors (ii) acceptors. (c) A direct-gap semiconductor is doped to produce a density of 1023electrons/m3. Calculate the hole density at room temperature given that the gap is 1.0 eV, and the effective mass of carriers in the conduction and valence band are 0.25 and...
[590] The band stru energy. What is the minimal photon energy to directly excite an electron from the valence band to the conduction band? A. 0.7 eV B. 0.8 eV C. 1.2 eV D. 1.5 eV cture for an imaginary semiconductor is shown in Figure 2, where Er is the Fermi CJ 1.2 eV Ef 0.8ev 1.5 ev Figure 2
(A) Comment on the energy needed to excite an electron from the valence band edge to conduction band edge of InP if the temperature is reduced from 300K to 77K. Justify your answer (B) If the semiconductor is undoped, how does the probability of occupancy of a state at the conduction band edge change as the temperature of the semiconductor is increased? Justify your answer.
Question 8 Pure silicon at room temperature has an electron number density of about 5 × 1015 m3 and an equal density of holes In the valence band. Suppose that one of every 10° silicon atoms is replaced by a phosphorus atom. (a) Which type will the doped semiconductor be, n or p? (b) What charge carrier number density will the phosphorus add? (c) What is the ratio of the charge carrier number density (electrons in the conduction band and...
(a) Assuming that the Fermi level is at the midgap in the intrinsic silicon, calculate the probability of finding an electron at the bottom of the conduction band (E=Ec) for three different temperatures: 0K, 20C, 100C? (b) How are these probabilities related to the probabilities of finding a hole at E=Ev, which is the top of the valence band? (c) A sample of silicon is doped with 1016 cm-3 of arsenic and 3x1016 cm-3 of boron. Calculate n, p, and...
PART A: The electrons in solids can be found ____________in only certain discrete sharp energy states associated with their orbits.in energy states that overlap so that more than one electron is associated with a given energy level.in the same energy states as if the atoms forming the solid were far enough so that their interactions could be neglected.in closely spaced energy levels that form a continuous distribution of energy within a certain range.PART B: When an electron in the valence...
A wire is made of an intrinsic semiconductor whose bandgap is 1.0eV. The wire is 0.05microns in diameter and 1 micron long. Electrons have a mobility of 1000/cm V-sec and holes have a mobility of 200/cm V-sec. The effective mass of an electron in the conduction band is 1.2 and that of a hole in the valence band is 0.6. The semiconductor operates at room temperature. a. What is the probability of finding an electron at an energy 0.5eV above...