Semiconductors

Semiconductors are materials whose electrical conductivity lies between that of conductors and insulators. Their electrical conductivity can be altered by external factors and due to these properties they are the fundamental components of modern electronic devices. Today, many technological products such as mobile phones, computers, televisions, medical devices and solar panels among others operate thanks to semiconductors.

Science fiction scenes are increasingly becoming reality in our lifestyle, largely due to advances in semiconductor technology. Semiconductors form the basis of many devices we use across numerous fields from communication and shopping to banking and information processing.

_{Microchip using semiconductors -}KBT Science Site

Electrical conduction is achieved 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: Their electrical conductivity can be modified by external factors or through doping.

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

• 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 band gap can be overcome by external factors such as temperature or light, thereby increasing conductivity.

These semiconductors consist of a single element:

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

They are formed by the combination of two or more elements and offer different 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.

Carbon-based materials used in next-generation technologies such as flexible electronics and OLED displays.

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

• N-Type Semiconductors: Five-valent atoms such as phosphorus or arsenic are added to increase electron density.
• P-Type Semiconductors: Three-valent atoms such as boron or aluminum are added to increase hole density.

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

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, making the production of integrated circuits (ICs) possible.

The first electronic computer, ENIAC, was built from 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 the advancement of battery and power storage technologies.
• High processing speed: Enhanced the performance of devices such as computers and smartphones.
• Durability and long lifespan: Unlike mechanical parts, they do not suffer from wear and tear.

Semiconductors are critical in many sectors:

• Computing and Communication: 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.

Semiconductor technologies continue to advance rapidly. Current research focuses 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. In the future, graphene, perovskites and new organic semiconductors are expected to play a larger role in the electronics industry.

Semiconductors are one of the most important materials in the modern world. They have driven the advancement of electronic devices and fundamentally changed our lives. These materials, which form the foundation of today’s technology, will continue to lead the next generation of innovations.