Lecture 4

Question 1

Drift current

Answer 1

Electric current due to external electric field (voltage across the device)

Question 2

Physical unit for electric current

Answer 2

A = C/s

Question 3

electric current

Answer 3

Net flow of electric charge (I)

Question 4

Electric current density

Answer 4

A/cm^2

J = I/S

Question 5

Charge of a hole

Answer 5

Q = +e = 1.6*10^-19 C

Question 6

No empty states

Answer 6

No current

Question 7

What can contribute to electric current through a device

Answer 7

Charge carriers (e in conduction band, h+ in valence band)

Question 8

Ec

Answer 8

Bottom of conduction band

Question 9

Ev

Answer 9

Top of valence band

Question 10

Fermi-Dirac Distribution Function

Answer 10

Gives us the probability that a state is occupied by an electron

Particles indistinguishable, only one particle permitted in each quantum state (Pauli Exclusion Principle)

Question 11

Density of States Function (DOS)

Answer 11

The number of available states per unit volume per unit energy

Question 12

E < Ef

Answer 12

Large probability

Question 13

E > Ef

Answer 13

Small probability

Question 14

The probability that energy level E is occupied by an electron

Answer 14

Not 1 but very close to 1

Question 15

The probability that energy level E is empty (does not have an electron)

Answer 15

Not 1 but very close to 1