In a $p-n$ junction diode,the direction of diffusion current is from

Write a short note on a semiconductor diode.

The electrical resistance of the depletion layer is large because

In a $p-n$ junction diode, the current $I$ can be expressed as $I=I_{0} \left[\exp \left(\frac{e V}{k_{B} T}\right)-1\right]$, where $I_{0}$ is the reverse saturation current, $V$ is the voltage across the diode (positive for forward bias, negative for reverse bias), $I$ is the current through the diode, $k_{B}$ is the Boltzmann constant $(8.6 \times 10^{-5} \; eV/K)$, and $T$ is the absolute temperature. If for a given diode $I_{0}=5 \times 10^{-12} \; A$ and $T=300 \; K$, then:
$(a)$ What will be the forward current at a forward voltage of $0.6 \; V$?
$(b)$ What will be the increase in the current if the voltage across the diode is increased to $0.7 \; V$?
$(c)$ What is the dynamic resistance?
$(d)$ What will be the current if reverse bias voltage changes from $1 \; V$ to $2 \; V$?

$A$ potential barrier of $0.50 \ V$ exists across a $P-N$ junction. If the depletion region is $5.0 \times 10^{-7} \ m$ wide,the intensity of the electric field in this region is:

The voltage-current characteristic of a diode during forward bias is given by $I = 7.8 \times 10^{-5} e^{6.5 V_D}$, where $I$ is the current in $mA$ and $V_D$ is the diode voltage in $V$. Find the dynamic resistance of the diode in $\Omega$, when the current is $4 \ mA$.