A semiconductor acts like an ideal insulator at absolute zero temperature that is at zero kelvin. It is because the free electrons in the valence band of semiconductors will not carry enough thermal energy to overcome the forbidden energy gap at absolute zero.

The fermilevel energy and the probability of finding an electron having an energy is dependent on temperature. Therefore at absolute zero the semiconductor will definitely behave as an insulator.

At low temperature the valence band of a semiconductor is completely filled and the conduction band is completely empty. Therefore a semiconductor virtually behaves as an insulator at low temperature.

The Definition Of A Semiconductor With moderate conductivity, a semiconductor has a conductivity value between that of a conductor such as silver and an insulator, such as the mica we use in Elmelin’s product range.

A semiconductor allows very low charge particles to move from valence band to conduction band. In insulators, there is no flow of charge particles under the influence of electric field hence insulators are the bad conductor of electricity.

p-type and n-type materials are simply semiconductors, such as silicon (Si) or germanium (Ge), with atomic impurities; the type of impurity present determines the type of the semiconductor.

In n-type silicon, the electrons have a negative charge, hence the name n-type. In p-type silicon, the effect of a positive charge is created in the absence of an electron, hence the name p-type.

In N-type semiconductor, electrons are majority carriers and holes are minority carriers. In P-type semiconductor, holes are majority carriers and electrons are minority carriers. It has Larger electron concentration and less hole concentration. It has Larger hole concentration and less electron concentration.

In a N-type semiconductor, the majority of charge carriers are free electrons whereas the holes are in minority. In a P-type semiconductor, the majority of charge carriers are holes whereas the free electrons are in minority.

The most used semiconductor materials are silicon, germanium, and gallium arsenide.

When P-type and N-type come into contact, carriers, which are holes and free electrons, are attracted to each other, recombine at the junction of P-type and N-type, and disappear. Because there are no carriers near the junction, it is called a depletion layer, and it becomes the same state as an insulator.

There are two types of extrinsic semiconductors: p-type (p for positive: a hole has been added through doping with a group-III element) and n-type (n for negative: an extra electron has been added through doping with a group-V element).

Two main types of semiconductors are n-type and p-type semiconductors. (i) n-type semiconductors. Silicon and germanium (Group 14) have very low electrical conductivity in the pure state.

Two-terminal Semiconductor Devices

• Diode.
• Schottky Diode.
• Light Emitting Diode (LED)
• DIAC.
• Zener Diode.
• Photo Diode (Photo Transistor)
• PIN Diode.
• Laser Diode.

Some examples of semiconductors are silicon, germanium, gallium arsenide, and elements near the so-called “metalloid staircase” on the periodic table. After silicon, gallium arsenide is the second most common semiconductor and is used in laser diodes, solar cells, microwave-frequency integrated circuits, and others.

A semiconductor can help controlled flow of electricity. The basic function of such a device is to switch ON and OFF the flow of electricity as and when required. A semiconductor device can perform the function of a vacuum tube with hundreds of times its volume.

Semiconductors are an essential component of electronic devices, enabling advances in communications, computing, healthcare, military systems, transportation, clean energy, and countless other applications.

Semiconductors are employed in the manufacture of various kinds of electronic devices, including diodes, transistors, and integrated circuits. Such devices have found wide application because of their compactness, reliability, power efficiency, and low cost.

Semiconductors works due to imbalance of electrons that carry negative charge. This imbalance of electrons generates positive (where there are excess protons) and negative charges (where there are excess electrons) at two ends of surfaces of the semiconductor material. This is how semiconductor works.

Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard-brittle, grayish-white metalloid in the carbon group, chemically similar to its group neighbors silicon and tin. Pure germanium is a semiconductor with an appearance similar to elemental silicon.

Semiconductor memory is a digital electronic semiconductor device used for digital data storage, such as computer memory. It typically refers to MOS memory, where data is stored within metal–oxide–semiconductor (MOS) memory cells on a silicon integrated circuit memory chip.

What is Semiconductor Memory?

• Stores data in magnetic form.
• Affected by magnetic fields.
• Has high storage capacity.
• Doesn’t use a laser to read/write data.
• Magnetic storage devices are; Hard disk , Floppy disk, Magnetic tape etc.

What are the key properties of semiconductor memory? They exhibit two stable states, which can be represented by 0 or 1, they are capable of being written into to set the state, and they can be read to sense the state.

ROM is an acronym for Read-Only Memory. It refers to computer memory chips containing permanent or semi-permanent data. Unlike RAM, ROM is non-volatile; even after you turn off your computer, the contents of ROM will remain. Almost every computer comes with a small amount of ROM containing the boot firmware.

ROM stands for read-only memory. It’s used to store the start-up instructions for a computer, also known as the firmware. Most modern computers use flash-based ROM. It is part of the BIOS chip, which is located on the motherboard.

Memory Basics Computer memory is of two basic type – Primary memory(RAM and ROM) and Secondary memory(hard drive,CD,etc.). Random Access Memory (RAM) is primary-volatile memory and Read Only Memory (ROM) is primary-non-volatile memory.

Computer ROM A good example of ROM is the computer BIOS, which is a PROM chip that stores the programming needed to begin the initial computer startup process. Using a non-volatile storage medium is the only way to begin this process for computers and other devices. ROM-type storage is still used today.

ROM provides the necessary instructions for communication between various hardware components. Other advantages of ROM include: Its static nature means it does not require refreshing. It is easy to test. ROM is more reliable than RAM since it is non-volatile in nature and cannot be altered or accidentally changed.

RAM is a thin rectangular chip that you can find inserted in a slot on the motherboard, whereas ROM is typically an optical drive made of magnetic tapes. Furthermore, RAM is usually bigger than ROM.

The disadvantages of Erasable Programmable ROM (EPROM) are:

• The static power consumption is high as the transistors used have higher resistance.
• It is not possible for a particular byte to be erased, instead the entire content is erased.
• UV based EPROM takes time to erase the content.