Semiconductors

Semiconductors: Types and Their Impact on Our Lives

What Is a Semiconductor?

Semiconductors are materials whose electrical conductivity lies between that of conductors and insulators. Their electrical conductivity can be altered by external factors, making them fundamental components of modern electronic devices. Today, hand telephones, computers, televisions, medical devices and solar panels such as many other technological products operate thanks to semiconductors.

Our lifestyle, increasingly resembling scenes from science fiction films, is largely dependent on the advancement of semiconductor technology. Semiconductors form the foundation of countless devices we use daily, from communication and commerce to banking and information processing.

Electrical Properties of Semiconductors

Electrical conduction occurs through the movement of free electrons in materials. Based on their electrical properties, materials are classified into three main categories:

• Conductors: They have a high density of free electrons and conduct electricity easily (copper, gold, silver).
• Insulators: They have a low density of free electrons and do not conduct electricity (plastic, porcelain, wood).
• Semiconductors: Materials whose electrical conductivity can be modified by external factors or through doping.

Band Theory and Conductivity

The conductivity of materials depends on the energy levels of electrons. The energy band structure of a semiconductor consists of:

• Valence Band: The highest energy level occupied by electrons.
• Conduction Band: The energy level at which electrons can move freely.
• Band Gap: The energy difference between the valence band and the conduction band.

In semiconductors, this ban band gap can be overcome by external factors such as temperature or light, thereby increasing conductivity.

Types of Semiconductors

A. Elemental (Natural) Semiconductors

These semiconductors consist of a single element:

• Silicon (Si): The most widely used semiconductor in the electronics industry.
• Germanium (Ge): Has higher electron mobility than silicon but is more sensitive to temperature changes.
• Tin (Sn): Used in certain specialized electronic applications.

B. Compound Semiconductors

Formed by the combination of two or more elements, they offer diverse conductivity properties:

• Gallium Arsenide (GaAs): Ideal for high-frequency applications.
• Indium Phosphide (InP): Used in optoelectronic devices.
• Cadmium Telluride (CdTe): An efficient semiconductor in solar panels.
• Silicon Carbide (SiC): Used in high-temperature and high-power applications.

C. Organic Semiconductors

Composed of Carbon based materials, they are used in next-generation technologies such as flexible electronics and OLED displays.

Doping and Carrier Types

Safe semiconductors (intrinsic) generally have low conductivity. However, this can be altered through doping:

• N-Type Semiconductors: Created by adding pentavalent atoms (phosphorus, arsenic) to increase electron density.
• P-Type Semiconductors: Created by adding trivalent atoms (boron, aluminum) to increase hole density.

N-type and P-type semiconductors are combined to create electronic components such as transistors, diodes and integrated circuits.

Impact of Semiconductors on Our Lives

The development of semiconductor technology has significantly transformed the modern world. While early computers used vacuum tubes, semiconductor transistors were developed from the 1940s onward, enabling the production of integrated circuits (ICs).

The first electronic computer, ENIAC, consisted of vacuum tubes and occupied an area of 167 square meters. Today, processors containing billions of transistors operate within just a few square centimeters.

The advantages provided by semiconductors include:

• Small size and light weight: Enabled the portability of electronic devices.
• Low energy consumption: Supported advances in battery and power storage technologies.
• High processing speed: Enhanced the performance of computers and smartphones.
• Durability and long lifespan: Unlike mechanical parts, they do not suffer from wear and tear.

Applications of Semiconductors

Semiconductors are critical in numerous sectors:

• Computing and Communications: Microchips, RAM, processors.
• Energy: Solar panels, power electronics.
• Optoelectronics: LEDs, laser diodes, fiber optic systems.
• Medicine and Biotechnology: Sensors, medical imaging devices.
• Automotive: Electric vehicle batteries, radar and sensors.

The Future of Semiconductors

Semiconductor technologies continue to advance rapidly. Current research focuses particularly on next-generation chip manufacturing techniques, 3D transistors, quantum computers and carbon nanotubes on.

Additionally, as silicon approaches its physical limits, alternative materials are being explored. Graphene, perovskites and new organic semiconductors are expected to play increasingly significant roles in the electronics industry in the future.

Semiconductors are one of the most important materials in the modern world. They have driven the evolution of electronic devices and fundamentally transformed our lives. As the foundation of today’s technology, these materials will continue to lead the way in next-generation innovations.