Question

Calculate the concentration of holes and conduction electrons in intrinsic silicon at 300 K if m∗ e = 0.36me, m∗ h = 0.81me and Eg = 1.12 eV. What is the value of the Fermi energy?

Answer #1

For silicon at T=300K, Intrinsic carrier concentration
(??) = 1.45 × 10^10 ??−3 Silicon bandgap (?? = 1.12 ??) The silicon
is doped at room temperature (300K) with Arsenic atoms
(penta-valent), so that donor concentration is (??) =6× 10^16 cm-3
. Find the equilibrium concentration of electrons, holes and shift
of the chemical potential (Fermi level) with respect to intrinsic
chemical potential due to doping.

1. Compute the resistivity of an intrinsic semiconductor at 300
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2.
The intrinsic concentration of electrons and holes (i.e.
concentration of e-h pairs) in Si at room temperature is
approximately 1x1010 cm-3.
Given the density and atomic mass of Si to be 2.33 g/cm3 and
28.06 g/mol, determine the ratio of ionized to...

Solid State Physics
Find the number of free electrons in copper at 300 K with E = 5
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states g(E) and the Fermi-Dirac probability function f(E) to
estimate the number of free electrons. in a metallic solid You need
to multiply a small value of dE (let's say dE = 0.0001 eV) times
g(E) and f(E) and the given volume of 1 cm^3....

For aluminum (units of eV) at T = 0 K, calculate the Fermi
Energy of electrons. Assume that each aluminum atom gives up all of
its outer-shell electrons to form the electron gas. b) Find the
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is the Fermi velocity compared to the velocity of electrons with
kinetic energy equal to thermal energy at room temperature?

A p-type silicon-metal contact is made with aluminum (?M=4.75
eV). NA=5x1015/cm3, and kT=0.026 eV.
(a) Sketch to scale a thermal equilibrium band diagram for the
ideal case.
(b) Comment on the barriers for (i) electrons in the metal (ii)
electrons in the silicon (iii) holes in the silicon (iv) holes in
the metal
(c) If positive voltage is applied to the semiconductor, show
the carrier flux and energy band diagram.

The occupancy probability function can be applied to
semiconductors as well as to metals. In semiconductors the Fermi
energy is close to the midpoint of the gap between the valence band
and the conduction band. Consider a semiconductor with an energy
gap of 0.88 eV, at T = 320 K. What is the probability that (a) a
state at the bottom of the conduction band is occupied and (b) a
state at the top of the valence band is not...

1: A sample of silicon has a concentration of donors of 10^20
donors m^(-3). All donors are ionised and T = 300k
a: What is the fermi level?
b: At what temperature will the intrinsic electron concentration
become larger than the donor electron concentration?

The occupancy probability function can be applied to
semiconductors as well as to metals. In semiconductors the Fermi
energy is close to the midpoint of the gap between the valence band
and the conduction band. Consider a semiconductor with an energy
gap of 0.66 eV at T 310 K. What is the probability that (a) a state
at the bottom of the conduction band is occupied and (b) a state at
the top of the valence band is not occupied?...

.
The Figure below shows the schematic band diagram of an indirect
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band tend towards the conduction band minimum. For the following
calculations use the values of silicon: Indirect band-gap energy WG
= 1.13eV and lattice constant a = 0.543 nm.
(a) Calculatethefrequencyofaphotonthatcorresponds
to the band gap energy of silicon. How large is the momentum of
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.
Consider a silicon
sample at 300 K. Assume that the electron concentration varies
linearly with distance. At x=0, the electron concentration is n(0).
At x=10 µm, the electron concentration is n(10µm)=
5x1014/cm3. If the electron diffusion
coefficient, assumed constant, is Dn =30
cm2/sec, determine the electron concentration at x=0 for
the following two diffusion current densities: (a) the diffusion
current density is found to be Jndiff = + 0.9
A/cm2 and (b) Jndiff = - 0.9
A/cm2.

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