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PN JUNCTION PDF

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The p-n junction is the fundamental building block of the electronic age. Most electronic devices are made of sili- con. By exploring the electrical properties of. Semiconductor material doped with donors. Material has high concentration of free electrons. Concentration of holes in n-type material is very low. p-n junction. No current / thermal equilibrium. •PN Junction at equilibrium. 1st Step: diffusion mechanism. 2nd Step: built in Electric Field appears⬄ compensates diffusion.


Pn Junction Pdf

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Before going to the discussion of diode, we have to check the details of P-N In a step graded P-N junction, there exists a concentration gradient near the. One important feature of the pn junction is that current (holes) flows freely in the p to n direction Typical I-V static characteristics of a silicon pn junction diode. The p-n junction is a versatile element, which can be used as a rectifier, as an isolation structure and as a voltage-dependent capacitor. In addition, they can be .

A DOI The current—voltage characteristics of the oxide-based p—n junction showed a rectifying behaviour with turn-on voltage of 0.

The oxide-based p—n junction diode was irradiated to 80 MeV O? Decrease in grain size due to SHI irradiation is confirmed by the grazing angle X-ray diffraction and atomic force microscopy.

In comparison with the pristine p—n junction diode, O? For irradiated p—n junction diode, current—voltage curve has still rectifying behaviour but exhibits lower turn-on voltage than that of virgin p— n junction diode. Though, certain materials simultaneously fulfil the requirements of favourable conductivity and transparency.

An important criterion for materials that can be used in these applications is that they possess a high optical transparency in the visible range of the electromagnetic spectrum and high electrical conductivity.

Combination of conductivity and transparency in oxides is achieved by fabricating them with a non-stoichiometric composition or by introducing appropriate dopants. Among various oxide semiconductors, tin oxide, zinc oxide, titanium oxide, nickel oxide are particularly attractive materials [2—8]. In this work, Fe-doped SnO2 was used as n-type conducting oxide.

Because of its good adsorptive properties and chemical stability, it can be deposited on glass, ceramics, oxides, and substrate materials of other types.

It has a high melting point and good transmission of light in visible region of electromagnetic spectra, and it does not easily react with oxygen and water vapour in the air, so it has a high specific volume and good cycling performance [9]. On the other hand, lithium-doped nickel oxide Li:NiO has been used as a p-type semiconductor. NiO is a wide band gap semiconductor at room temperature [10, 11]. It has been demonstrated that change in electric properties can be induced by swift heavy ion irradiation SHI in binary oxides such as Li-doped NiO thin film [12] and In2O3 thin film [13].

There are reports on irradiation effects on SnO2 thin film for modifying its optical, electrical, Page 2 of 8 morphological, and gas-sensing properties.

It is possible to tune the properties by irradiating SnO2 thin film to particular ion fluences. Although, there are reports on the effects of ion irradiation on SnO2 thin film, there are no reports available on the irradiation effects on the diode structure based on Fe-doped SnO2 [14, 15].

For device fabrication, defects induced in semiconductor by radiation play an important role. The SHI irradiation of thin film has been subject of research because SHI can modify optical, electrical, and optoelectronic properties [16].

For SHI irradiation, the extent of damage formation and property modification depends strongly on energy, mass, and fluence of the ion and target density. Deposition of oxide semiconductors using pulsed laser deposition PLD under ultra-high vacuum UHV offer impurity-free environment as well as smooth interface with excellent stoichiometric control [10].

The fabricated p—n junction diodes were irradiated with O?

Pristine SnO2 is an n-type semiconductor having very low conductivity. Transition metal doping such as Fe2? On the other hand, higher doping levels of Fe would degrade its optical transparency. Moreover, low or dilute doping is also desirable for preserving the single crystallographic SnO2 phase [5—7].

Earlier, we have shown that 10 at. The laser pulse repetition rates and laser powers were fixed at 10 Hz and 2. Substrate temperature of B.

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Mistry et al. Hall, W.

Multiple Choice Questions (MCQs)

Dunlap, Jr. Pearson, B. Sawyer: Silicon p-n junction alloy diodes. Teal, E. Buehler: Growth of silicon crystals and of single crystal silicon p-n junctions.

Frank, V. Gummel: Hole-electron product of p-n junctions. Solid State Electron. Dermenzhi, A. Herlet: The maximum blocking capability of silicon thyristors.

Solid-State Electron 8, Google Scholar 3. Zener: Proc. London , CrossRef Google Scholar 3. Sze, G. Esaki: New phenomenon in narrow germanium pn junctions. Kane: Theory of tunnelling.

Multiple Choice Questions (MCQs)

Kane: Thomas—Fermi approach to impure semiconductor band structure. By the movement of electrons and holes current flows. In this condition, the width of the depletion region decreases due to the reduction in the number of positive and negative ions.

Forward Bias Condition V-I Characteristics By supplying positive voltage, the electrons get enough energy to overcome the potential barrier depletion layer and cross the junction and the same thing happens with the holes as well.

The amount of energy required by the electrons and holes for crossing the junction is equal to the barrier potential 0. This is also known as Voltage drop. The voltage drop across the diode occurs due to internal resistance.

This can be observed in the below graph. Forward bias V-I Characheristics Reverse Bias In the forward bias condition, the negative terminal of the battery is connected to the N-type material and the positive terminal of the battery is connected to the P-type material. This connection is also known as giving positive voltage.

p–n junction

Hence, the electric field due to both the voltage and depletion layer is in the same direction. This makes the electric field more stronger than before. Due to this strong electric field, electrons and holes want more energy to cross the junction so they cannot diffuse to opposite region.

Hence, there is no current flow due to lack of movement of electrons and holes. Depletion layer in Reverse Biased condition The electrons from the N-type semiconductor are attracted towards the positive terminal and the holes from the P- type semiconductor are attracted towards negative terminal. This leads to the reduction of the number of electrons in N-type and holes in P-type. In addition, positive ions are created in N-type region and negative ions are created in the P-type region.For a Fig.

Multiple Choice Questions PNJunction

This effect is used to advantage in Zener diode regulator circuits. Such sharp increases in the temperatures give rise to liquid phase sintering in an extremely small time domain, which in turn, may enhance crystallinity or lead to amorphization of the target material. Zero Biased Condition In this case, no external voltage is applied to the P-N junction diode; and therefore, the electrons diffuse to the P-side and simultaneously holes diffuse towards the N-side through the junction, and then combine with each other.

The regions near the p—n interface lose their neutrality and most of their mobile carriers, forming the space charge region or depletion layer see figure A. Sparks, E.

Zener: Proc. The increase in resistance of the p—n junction results in the junction behaving as an insulator. Moscow 1, ;The rectifying action of semiconductors.