Category: Index
-
Heaviside-Lorentz Units
Introduction Heaviside-Lorentz units (named for O. Heaviside and H.A. Lorentz) constitute a particular extension of CGS units which are most often useful in theoretical electrodynamics. As a practical system of units, Heaviside-Lorentz falls short due to most measureable quantities being excessively small or big for intuition. Neverless, Heaviside-Lorentz showcases the simplicity and beauty of the…
-
Conduction Band
Introduction to Energy Bands In solids, electrons are not associated with individual atoms, but are spread throughout the material. Because of the close proximity of the atoms, the atomic energy levels overlap, forming continuous energy bands. The electron energy in solids is therefore not discrete, but rather exists within these energy bands. The conduction band…
-
Valence Band
Introduction In the realm of solid-state physics, understanding electronic band structure is essential for appreciating the electrical, optical, and thermal properties of materials. Among various energy bands, the valence band holds a pivotal position. It helps in explaining numerous phenomena, such as electrical conductivity, superconductivity, and optical absorption. Energy Bands in Solids In an isolated…
-
Ultracold Atoms
Introduction Ultracold atoms are atomic particles that have been cooled to temperatures close to absolute zero (0 Kelvin or -273.15 degrees Celsius). At such extremely low temperatures, atoms behave in ways that defy our everyday understanding of the physical world. This is due to quantum mechanical effects that become more pronounced at ultracold temperatures, leading…
-
Junction Diode
Introduction to Junction Diodes A junction diode, commonly referred to simply as a diode, is a fundamental electronic component used in various circuits. Its primary function is to allow electric current to flow in one direction while blocking the flow in the opposite direction. This makes diodes particularly useful in applications such as rectification, voltage…
-
Intensity
Introduction to Intensity In physics, intensity is a measure of the energy flux, or the power per unit area. It is commonly used to describe various phenomena such as light, sound, and electric fields. It quantifies how much energy passes through a specific area in a given time period. Mathematical Definition of Intensity In the…
-
Kelvin Probe Force Microscopy (KPFM)
Introduction to KPFM Kelvin Probe Force Microscopy (KPFM), also known as Surface Potential Microscopy, is a powerful scanning probe microscopy technique used to measure the contact potential difference (CPD), or electrostatic surface potential, between the tip of a probe and the sample surface. The technique is based on the original work of Lord Kelvin, who…
-
Impedance Matching
Introduction Impedance matching is a fundamental concept in electrical engineering and physics, particularly regarding the transmission and reflection of waves. In the most basic sense, impedance matching involves making the output impedance of a source equal to the input impedance of a load to maximize the power transfer or minimize signal reflection. Concept of Impedance…
-
Extrinsic Semiconductors
Introduction Extrinsic semiconductors are a specialized type of semiconductors that are chemically modified (or ‘doped’) to enhance their electrical conductivity. Unlike intrinsic semiconductors, which consist solely of one type of atom, extrinsic semiconductors have been intentionally doped with impurities to create a surplus of free charge carriers, either electrons or holes. Doping Process The process…
-
Intrinsic Semiconductors
Introduction Intrinsic semiconductors, sometimes referred to as pure semiconductors, are materials that are not doped by impurities and consist only of one type of atom. They represent an essential class of materials that have revolutionized the world of electronics and underpin the operation of devices such as transistors, diodes, and solar cells. Basic Concept: Band…