Question #43765

A p-n junction photodiode has a built-in potential $V_{bi} = 0.8 \text{ V}$. It is illuminated by a constant photon flux, resulting in a uniform generation rate $G$ of electron-hole pairs per unit volume throughout the depletion region. Assume the photocurrent $I$ is entirely due to the drift of these generated carriers across the depletion region. At a reverse bias voltage $V_{R1} = 2.8 \text{ V}$, the steady-state photocurrent is $I_1 = 2.0 \text{ \mu A}$ and the average drift velocity of electrons is $v_1 = 1.0 \times 10^4 \text{ m/s}$. If the reverse bias voltage is increased to $V_{R2} = 13.6 \text{ V}$ while keeping the photon flux constant, determine the new photocurrent $I_2$ and the new average drift velocity $v_2$. (Assume the electron mobility $\mu_e$ is constant, and the depletion width $W$ follows the relation $W \propto \sqrt{V_{bi} + V_R}$).