semiconductor physics assignment help

semiconductor physics assignment help

Exploring the Fundamentals of Semiconductor Physics

1. Introduction to Semiconductor Physics

Semiconductors are an entire class of materials with properties not quite like conductive (such as copper, gold, and graphite) or insulating (such as wood, rubber, and glass) materials. We are going to explore some of the fundamental properties of semiconducting materials, such as crystals and energy band structure. In order to apply these properties to practicable devices, we will discuss how electrons and “holes” produced by ionizing radiation from semiconductors. In order to do this, the above concepts of charge carriers will be presented in such a means that the model formulated for metallic conductors is indirectly applied to the semiconductors. Carriers are also equally important in conducting current in semiconductors and are affected by a number of the same physical processes. The final section addresses properties of particular interest in current nanostructure applications.

Semiconductor materials are integral to the creation of a variety of useful electronic devices. A good understanding of the basics of semiconductor physics is valuable, since the important fundamental concepts can be leveraged in a variety of situations. This paper aims to explain important physical properties of semiconductors, as well as carrier generation, recombination, and transport. In addition, device features like p-n junctions (and the diode-like characteristics they exhibit) and semiconducting MOS capacitors will be presented. It is extremely important that the basic physics of these useful electronic materials is thoroughly understood, as this will facilitate better design, analysis, and interpretation of various devices and structures.

2. Intrinsic and Extrinsic Semiconductors

An intrinsic semiconductor is a pure semiconductor at its best, but it shows very few charges to conduct a little bit, almost a good deal of resistance, and it is hardly used in the electronics field. We can’t find too many applications for it, still, it’s necessary to learn to get a basic idea about pure semiconductors. Likewise, above we get the definition of the intrinsic semiconductor. In short, the semiconductor when it does not get mixed with any impurities to attract more charge is termed as an intrinsic semiconductor. Overall, we can define intrinsic semiconductors as semiconductors without impurities. Conductivity depends on the electrical energy gap. In extrinsic semiconductors, conductivity depends upon the dopants added. The number of charge carriers increases the conductivity. The current carriers are of two types: electrons and holes. Under the influence of the electrical field, the movement of an electron occurs from negative to positive or positive to negative plate, and in the case of a hole, the travel is from the positive plate of a battery to the negative plate of a battery.

All semiconductors are not created identical. We can encounter two different types of semiconductors according to the availability of free electrons in a pure semiconductor. Pure semiconductors are nothing but semiconductors that have only one kind of charge carriers. This article provides a comprehensive and concise explanation of the distinction between intrinsic and extrinsic semiconductors and the variation between them briefly without deviating from the real idea related to the subject.

3. Carrier Transport in Semiconductors

The carrier concentration given in equations (3) and (5) is an uninteresting number if the carriers are just diffusing away as fast as they are generated. However, in a semiconductor, some relatively small number of carriers can be generated and separated from the majority extrinsic charge carriers (i.e., electrons in n-type, holes in p-type material) by an applied electric field. This is the central aspect of a semiconductor’s usefulness in electro-optic and electronic devices. Not much of interest happens if the minority carriers are in vanishingly small amounts, other than a very slight change in the local band-bending from the bulk nB – p bulk expression. As these carrier concentrations increase, not only does the local bandbending become more dominated by these carriers, but also new mechanisms emerge for some carriers to contribute to detectable high-speed transport of electrons in the conduction band, and holes in the valence band.

This third part of our primer starts with the transfer of charge carriers, popularly referred to as carrier transport within the material, especially over a distance which is relevant for the upcoming introduction to the diodes, a typical process that is associated with carrier injection into a semiconductor.

After having considered the fundamentals of semiconductor physics, thereby addressing the basic band structure and oscillatory properties, and how extrinsics are determined, one has a background to understand the transport of carriers in semiconductors. The final goal of creating semiconductor devices is to place usually either electrons in the conduction band or holes in the valence band, employing the natural potential gradient existing in semiconductor material and let these carry the appropriate reversed charge.

4. Semiconductor Devices and Applications

A diode is the simplest semiconductor device, consisting simply of a pn junction or an abrupt or gradual p-n junction in a medium or other junction between a metal and a semiconductor. Transit time and impact ionization are active at high fields. A bipolar junction transistor is equivalent to two closed diodes as shown in Fig. 1.1. There are many different regions of operation of this device because both types (n and p) of semiconducting material are present at the emitter-base and the base-collector junctions. Gates and channels are added to field effect transistors. The charge in the channel can be dominant, in which point it is a metal oxide field effect transistor (MOSFET); negatively charged ions are used in the channel. In this section, the basic functionalities and structures of semiconductor devices will be explained. This will be followed by a discussion of the operating principle of the devices. Hosts of devices are based on one or more diode, bipolar, or MOSFET transistors in various combinations.

Semiconductors are versatile materials that have found applications in the fabrication of a wide variety of devices. These devices range from diodes and transistors to memory chips, microprocessors, solar cells, and sensors. They are the fundamental components of integrated circuits, or chips, that have revolutionized information technology by allowing the miniaturization of electronic systems. At the heart of virtually all these technologies is the semiconductor, and the fundamentals of these technologies are unique to semiconductor physics. This chapter is designed to provide a grounding in the properties of semiconductor junctions and devices suitable for subsequent areas of study in semiconductor technology.

5. Recent Advances and Future Directions

One of the motivations here in discussing this frontier area of science in semiconductor physics is to visualize the potential of moving forward in the field. Technological advances always feed from new science that opens up with this exciting area. The special properties of quantum systems in 2D layers formed by hexagonal compounds are not only of interest for the solid-state physicist examining its statistical mechanical properties but also to the principles of superconductivity. It has opened for the researchers, both theoretical and experimental, a new field of many-body physics in solid state. The large body of literature has already reported the presence of BCS-like hole superconductivity. Then, the question arises as to what further has our understanding reached in this field. In the limited scope where space has hedged us in this article, we would like to delve into the latest in the superconductivity arising from chalcogens and what the future directions are.

Even though semiconductor physics has been primarily about silicon till now, recent progress in tuning electronic properties of layer systems formed by hexagonal chalcogenides (TMD) or other layered compounds has opened up a cascade of fascinating phenomena. These two-dimensional (2D) systems are of interest not only to the solid-state physicist but also to the device technologists who design a variety of electronic, chemical, and mechanical devices based on them. The 2D grating of electrons (holes) at the Fermi energy exhibits many-body quantum phenomena, where the states associated with these electrons are strongly correlated due to large interaction energy that is comparable to the Fermi energy itself. All this points to the strong possibility of observing new quantum phases of matter which emerge from many-body correlations between electrons. It thus presents immense possibilities for future discoveries and technological innovations, and fortunately, nature provides in the form of superconducting and magnetic and other quantum phases that such systems can expand to.