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Solid State Devices > Definitions > Flashcards

Definitions Flashcards

1
Q

What are the 3 important Lattices. What do they look like?

A

Simple cubic -> Looks like a box
Body-Centered cubic -> Looks like a box with an atom in the middle
Face-centered cubic -> Looks like a box with and atom on every face

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2
Q

What is the packing factor equation?

A

Packing Factor = (Number of Atoms in cell * Volume of Atom) / Vol Of Cell.
PF of sc -> 0.52
PF of bcc -> 0.68
PF of fcc -> 0.74

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3
Q

What law to use to find the lattice constant? Look for it on the equation sheet

A

Vegard’s Law -> Second Equation on sheet

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4
Q

What is are Miller indices?

A

Used to describe various crystal planes and directions

  • > Defined by where the planes cross the axes
  • > If a plane is parallel to an axis, the Miller index for that direction is zero
  • Defined with () brackets. No negatives, use bars.
  • Can be found by taking intercept of plane. Then reciprocals, then set to the same denominator and use the numerator as the miller indices
  • Have families. Basically depending on how you look at a plane, a bunch of different ones could be the same. So they’re a family
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5
Q

What are photons? Equation?

A

Packets of energy (Discrete Units)
E_elec = eVs = hv - workFunction
-> On equation sheet first page left side

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6
Q

Bohr Model Angular Momentum Variable

A

L -> On equation sheet left side first page

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7
Q

Energy of a photon emitted equation

A

Hv = Ei - Ef -> On equation sheet, first page left side

E i and E f = (1 Rydberg) / (Orbital ^2)

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8
Q

In Quantum Mechanics, what can every particle be described with? What happens with probability and particles?

A

Wave function! The wave function collapses when particle is found. Looks like a Gaussian distribution of where particle could be.

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9
Q

What is one weird ass thing Quantum particles do that are different from normal ones (Dealing with interference)

A

Quantum particles interfere with their own existence. Causing strange effects (like waves from what I’ve seen).

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10
Q

What is the infinite Potential Well equation?

A

E = (h_bar*Pi^2 * n ^ 2) / (2 * m * L ^ 2)

- > On first page left side bottom

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11
Q

What happens to a particle when it Tunnels?

A

The amplitude of the wave (particle) exponentially decreases as the width of the barrier increase

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12
Q

What is Zero Point Energy?

A

Quantum state with lowest possible energy level

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13
Q

What is the Casimir Effect?

A

Small attractive forces that act between two close parallel uncharged conducting plates. Due to quantum vacuum fluctuations of the electromagnetic field

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14
Q

What is the band gap in semiconductors? Where is it?

A

The band gap is the difference between the conducting band and the valence band. The intrinsic fermi level is actually in the middle of these two! Caused the the probabilistic location of an electron at a given point.

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15
Q

How do electrons move in a crystal?

A

The hop from atom to atom in a crystal. And they see a potential barrier every time they jump (Potential finite wells).

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16
Q

What is an Exciton?

A

A state of an electron and hole that looks like a Hydrogen atom. They’re attracted to each other by Coulombs electrostatic force.

17
Q

What variable represents Density of States? And where are the equations? What is it?

A

g! They’re on the first page chilling on the right, top. Density of States means the amount of possible states and electron can be in given a per unit volume. Hence, density of states.

18
Q

What variable represents the wave number?

A

K! For a given system. Wavenumber is the amount of phase difference per unit length.

19
Q

What is Effective Mass? Different types?

A

It is a tensor quantity, meaning it is a part of the Magnitude, direction and plane of an electron. There is conductive effective mass and density of states effective mass.
-> Conductive effective mass is used for conductive questions and I have no idea why density of states effective mass would be used…

20
Q

What variable represents Fermi-Dirac Distribution? What is it?

A

F_f (probability)! It is the probability of finding electronics at a given energy level (Sounds useful!)

21
Q

What is an intrinsic semiconductor? What are variables associated with it? (I.E Electrons, holes)

A

A Pure crystal no impurities or defects.
N is concentration of electrons in conduction band
P is concentration of holes in valence band
For intrinsic n = p = n_i
N_o, P_o is equilibrium densities (concentrations)

22
Q

What is the construction of the Electron Counting equation? Or Hole counting

A

N_o = g(Density of States) * f_f(probability)
Gives you number of electrons at equilibrium
Same thing for holes

23
Q

What are the variables for the DOS for valence and conduction bands

A

N_v is density of states variable for valence band

N_c is density of states variable for conduction band

24
Q

Impurity State Density variables?

A

n_d = density of electrons bound to donors
N_d = density of donors
N_d+ = density of ionized donors (Donors that have an electron)
n_d = N_d - N_d+
Same for holes
P_a = density of holes bound to acceptors

25
Q

What are the units of Drift Current? What is the general equation for it?

A

A / cm^2

-> J = q (electron) * N (Volume density cm^-3) * average velocity of electrons

26
Q

What does electron mobility mean?

A

Characterizes how quickly an electron can move through a metal or semiconductor. Carrier Mobility referees in general to both electron and hole mobility in semiconductors

27
Q

What can the Hall effect do for you? Variable looks like?

A

Used to determine the type of semiconductor as well as density and mobility of the majority carrier.
-> Uses V_h on second page left side

28
Q

What is in the Einstein Relation?

A

It can give you the defusion coefficients for holes and electrons.

29
Q

For PN junctions, what variables are re-defined because there aren’t enough variables in the world?

A

N_a and N_d to the Net concentration of their respective regions

30
Q

For the built in Voltage what are the variables used?

A 
P_p is hole concentration in p-type
P_n is hole concentration in n-type
n_p is electron concentration in p_type
n_n is electron concentration in n-type
V_bi is built in voltage
W is width
31
Q

What are the variables for Reverse Bias? One sided Junction?

A

Same as built in voltage normal bias.
Special equation can be used because the width of the space charge region can be equal to either the x_p or x_n if N_d or N_a is much much greater than the other.

32
Q

Miller shit -> What do all the other flipping symbols mean?

A

Miller Indices use ( ) brackets
Direction of perpendicular plan is [ ] brackets
Family of similar/symmetry directions < > things
Families of planes use { }

Solid State Devices (1 decks)

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