Write the general equation governing the photo generation phenomenon in a PN junction diode. In the equation you should have the current-term due to the voltage biasing and the photo generated current term due to an incident light. Mark the terms in your provided equation. (1) Draw the I-V current relation (I versus V plot) for changing gop (rate of optical generation). (2) Which quadrant of this I-V relation is utilized for solar-cell applications. (mark in your I-Vcurve)? (3) Which quadrant of the I-V relation is utilized for photo-detector application (mark in your I-Vcurve)? Now consider the photogeneration current term. What will be the effect on photo generated current, if the P and N sides are highly doped in comparison to light doped. (hint: how depletion region width changes? How does depletion width change the current?)

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