Chapter 12, Problem 16ICA

The following graph shows the relationship between current and voltage in a 1 N4148 small signal diode (a semiconductor device that allows current to flow in one direction but not the other).

Semiconductor diodes can be characterized by the Shockley equation:

$I_D=I_0\left(\frac{q{V}_D}{enKT}-1\right)$

Where

l_Dis the diode current [amperes]

1₀ is the reverse saturation current, constant for any specific diode

q is the charge on a single electron, 1.602 x 1 o-19 coulombs

V_D is the voltage across the diode [volts]

n is the emission coefficient, having a numerical value typically between 1 and 2, and constant for any specific device.

k is Boltzmann's constant, 1.381 x 10^-23 joules per kelvin

T is the temperature of the device [kelvin]

1. a. What are the units of the 1 following the exponential term? Justify your answer.
2. b. If the device temperature is 100 degrees Fahrenheit, what are the units of the emission coefficient, n, and what is its numerical value? (Hint: Electrical power [W] equals a volt times an ampere: P = VI. One ampere equals one coulomb per second.)
3. c. What is the numerical value and units of the reverse saturation current, 10? Use an appropriate metric prefix in your final answer.