A typical photovoltaic solar cell used to convert sunlight directly into electricity is primarily made from which material?

Introduction / Context:
This question is from basic physics and renewable energy. It asks what material is used to make a typical solar cell that converts sunlight into electrical energy. Understanding the basic construction of photovoltaic cells helps in studying solar power and modern energy technologies.

Given Data / Assumptions:

• The device in question is a solar cell, also called a photovoltaic cell.
• Options list carbon, gallium, silicon, and Teflon as possible main materials.
• Standard knowledge about commonly used semiconductor materials is assumed.

Concept / Approach:
Solar cells work on the principle of the photovoltaic effect, where light striking a semiconductor material generates a flow of electrons and therefore an electric current. The most widely used semiconductor for solar cells is silicon, often in crystalline or polycrystalline form. Silicon wafers are doped with impurities to create p type and n type layers, forming a p n junction that separates charge carriers when illuminated. Gallium is used in some specialised semiconductor devices and in compound semiconductors such as gallium arsenide, but the typical, mass produced solar panels on rooftops and fields are primarily silicon based. Carbon in the form of graphite and Teflon, a non conducting polymer, are not the principal active materials in standard photovoltaic cells.

Step-by-Step Solution:

Verification / Alternative check:
Physics and electronics textbooks on solar energy describe crystalline silicon and polycrystalline silicon solar cells as the most common type. They explain how silicon wafers are processed, doped, and assembled into modules. While there are thin film technologies using materials like cadmium telluride or amorphous silicon and some high efficiency cells using gallium arsenide, the baseline exam answer remains silicon. This confirms that silicon is the primary material for typical photovoltaic cells considered in basic science courses.

Why Other Options Are Wrong:

Carbon, arranged as graphite layers, is incorrect because graphite is used in electrodes and other applications but is not the main semiconductor material in standard solar cells.

Gallium, in pure metallic form, is wrong because although gallium compounds are used in some advanced devices, typical solar panels are not made primarily of pure gallium.

Teflon, a non conducting polymer, is incorrect because Teflon is an insulating material used for coatings and wire insulation, not as the active semiconductor in photovoltaic cells.

Common Pitfalls:
Students may be distracted by gallium, thinking of advanced semiconductors and assuming that the more exotic material must be correct. Others may confuse general carbon based electronics research with standard commercial practice. The safest approach in exam questions is to remember that the mainstream solar industry is built around silicon technology, unless the question clearly specifies an unusual cell type.

Final Answer:
A typical photovoltaic solar cell is primarily made from Silicon, a semiconductor material that converts sunlight into electricity.