Physics · Semiconductor Electronics : Materials, Devices And Simple Circuits · NEET
Neither. Unlike a photodiode (which works under reverse bias), a solar cell uses NO external battery at all. Light itself generates the charge carriers, and the junction's built-in field separates them to create a voltage. So a solar cell is self-powered; it is a source of EMF, not a device that needs an outside supply.
Because the cell delivers power instead of consuming it. Light drives current backward through the cell (opposite to a normal forward diode current), but the cell still develops a positive voltage. Positive voltage plus negative current puts the curve in the fourth (IV) quadrant. This exact fact was tested in NEET 2024.
A photodiode is operated under reverse bias and is used to DETECT or measure light (its reverse current changes with light intensity). A solar cell has no external bias and is used to GENERATE electrical power from light. Both are light-sensitive p-n junctions, but one senses light and the other supplies energy.
Voc is the voltage across the cell when no current is drawn (terminals open) - it is the maximum voltage the cell can give. Isc is the current when the terminals are shorted together (voltage zero) - it is the maximum current. These two points are the ends of the I-V curve in the fourth quadrant, and both increase when light intensity increases.
So that light can reach the junction easily. Electron-hole pairs must be created within or very near the depletion region, because only there does the built-in electric field separate them before they recombine. A thin top layer and a large surface area let more photons reach the junction and produce more current.
Given below are two statements: Statement I: Photovoltaic devices can convert optical radiation into electricity. Statement II: Zener diode is designed to operate under reverse bias in breakdown region. In the light of the above statements, choose the most appropriate answer.
Consider the following statements A and B and identify the correct answer: A. For a solar cell, the I-V characteristic lies in the IV (fourth) quadrant of the given graph. B. In a reverse biased p-n junction diode, the current measured in microamperes is due to majority charge carriers.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
A solar cell is a p-n junction diode that turns sunlight straight into electricity, without any moving parts and without an external battery.
Silicon is the most common material. Other materials such as gallium arsenide (GaAs) and cadmium telluride are also used because they absorb sunlight well and have a suitable energy gap.
No. A solar cell only produces electricity while light falls on it. To store the energy you must connect it to a battery or capacitor.
Mainly the light intensity and the area of the cell. More light and larger area create more electron-hole pairs, so more current flows. The energy gap of the material also matters.
It acts as an active source of EMF when light falls on it, because it supplies electrical energy to a circuit without needing an external supply.
