physics-class-12-unit-14-chapter-03-p-n-junction-basics-l-3-8-71o6wplux3i

<p><Success style="float:center;text-align:center;font-size:28px;" ><B>P-n Junction Basics</B></Success></p>
<p><Primary style="float:center;text-align:center;font-size:24px;"><B>Semiconductor</B></Primary></p>
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<p>The conduction properties of a semiconductor can be precisely controlled by doping an element with less or more valency</p>
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<p>For Si (or Ge), doping a pentavalent impurity such as Phosphorus or Arsenic, makes conduction electron concentration much higher than the hole concentration</p>
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<p>These are called n(negative)-type Semiconductors and the impurities are called donor impurities</p>
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<p><img alt="image" src="/subject-images/iitpal/image/physics-class-12-unit-14-chapter-03-p-n-junction-basics-l-3_8-71o6wplux3i-01.jpg"></p>
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<span style="color:blue">Semiconductor</span>$\to$N-Type Semiconductors$\to$Drift Velocity$\to$Ohm's Law$\to$Impurity Levels$\to$Hydrogen Atom$\to$P-n Junction$\to$Deplition Region$\to$Potential Barrier
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<p>======</p>
<p><Success style="float:center;text-align:center;font-size:28px;" ><B>P-n Junction Basics</B></Success></p>
<p><Primary style="float:center;text-align:center;font-size:24px;"><B>N-Type Semiconductors</B></Primary></p>
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<p>In n-type semiconductors, impurity levels are created slightly (few tens of meV) below the conduction band and are occupied by the extra electrons attached to the impurity ions</p>
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<p>Due to thermal energies, a large number of them go to the conduction band, increasing $n_e$. Intrinsic concentration is of the order of $10^{10}  {cm}^3$, but the impurity electrons forpm type doping could be around $10^{16}  {cm}^3$</p>
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<footer style='font-size:18px'>
Semiconductor$\to$<span style="color:blue">N-Type Semiconductors</span>$\to$Drift Velocity$\to$Ohm's Law$\to$Impurity Levels$\to$Hydrogen Atom$\to$P-n Junction$\to$Deplition Region$\to$Potential Barrier
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<p>======</p>
<p><Success style="float:center;text-align:center;font-size:28px;" ><B>P-n Junction Basics</B></Success></p>
<p><Primary style="float:center;text-align:center;font-size:24px;"><B>N-Type Semiconductors</B></Primary></p>
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<li>Increased number of electron concentration enhances the rate of recombination of electronholes and the hole concentration further reduces</li>
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<p>$n_e n_h=n_i^2$ (Independent of doping)</p>
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<p><img alt="image" src="/subject-images/iitpal/image/physics-class-12-unit-14-chapter-03-p-n-junction-basics-l-3_8-71o6wplux3i-03.jpg"></p>
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<hr>
<footer style='font-size:18px'>
Semiconductor$\to$<span style="color:blue">N-Type Semiconductors</span>$\to$Drift Velocity$\to$Ohm's Law$\to$Impurity Levels$\to$Hydrogen Atom$\to$P-n Junction$\to$Deplition Region$\to$Potential Barrier
</footer>
<p>======</p>
<p><Success style="float:center;text-align:center;font-size:28px;" ><B>P-n Junction Basics</B></Success></p>
<p><Primary style="float:center;text-align:center;font-size:24px;"><B>N-Type Semiconductors</B></Primary></p>
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<main>
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<p>For Si (or Ge ), doping a trivalent impurity such as Boron or Aluminium, makes hole concentration much higher than conduction electron concentration</p>
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<p>These are called p-type Semiconductors and the impurities are called acceptor impurities</p>
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<p><img alt="image" src="/subject-images/iitpal/image/physics-class-12-unit-14-chapter-03-p-n-junction-basics-l-3_8-71o6wplux3i-04.jpg"></p>
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</main>
<hr>
<footer style='font-size:18px'>
Semiconductor$\to$<span style="color:blue">N-Type Semiconductors</span>$\to$Drift Velocity$\to$Ohm's Law$\to$Impurity Levels$\to$Hydrogen Atom$\to$P-n Junction$\to$Deplition Region$\to$Potential Barrier
</footer>
<p>======</p>
<p><Success style="float:center;text-align:center;font-size:28px;" ><B>P-n Junction Basics</B></Success></p>
<p><Primary style="float:center;text-align:center;font-size:24px;"><B>N-Type Semiconductors</B></Primary></p>
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<main>
<div style='float: left; text-align: left; font-size: 22px; width:70%;'>
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<p>In p-type semiconductors, impurity levels are created slightly (few tens of meV) above the valence band and are vacant</p>
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<p>Due to thermal energies, valence electrons can jump to these impurity levels making holes in the valence band, increasing $n_h$. Intrinsic concentration is of the order of $10^{10} {cm}^3$, but the hole concentration for_ppm type doping could be around $10^{16}  {cm}^3$</p>
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</ol>
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<div style='float: right; width:30%;'>
<img src="https://imagedelivery.net/YfdZ0yYuJi8R0IouXWrMsA/c3316510-c218-4296-d124-f738adb70700/public">

</div>
</main>
<hr>
<footer style='font-size:18px'>
Semiconductor$\to$<span style="color:blue">N-Type Semiconductors</span>$\to$Drift Velocity$\to$Ohm's Law$\to$Impurity Levels$\to$Hydrogen Atom$\to$P-n Junction$\to$Deplition Region$\to$Potential Barrier
</footer>
<p>======</p>
<p><Success style="float:center;text-align:center;font-size:28px;" ><B>P-n Junction Basics</B></Success></p>
<p><Primary style="float:center;text-align:center;font-size:24px;"><B>N-Type Semiconductors</B></Primary></p>
<hr>
<main>
<div style='float: left; text-align: left; font-size: 22px; width:100%;'>
<ol start="11">
<li>Increased number of hole concentration enhances the rate of recombination of electron-holes and the electron concentration further reduces.</li>
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<p>$n_e n_h = n_i ^2$</p>
<p>$n_i$ = Concentration of e or h when no dopping is done</p>
<p>$n_e = n_h = n_i$</p>
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<div style='float: right; width:0%;'>
<p><img alt="image" src="/subject-images/iitpal/image/physics-class-12-unit-14-chapter-03-p-n-junction-basics-l-3_8-71o6wplux3i-06.jpg"></p>
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</main>
<hr>
<footer style='font-size:18px'>
Semiconductor$\to$<span style="color:blue">N-Type Semiconductors</span>$\to$Drift Velocity$\to$Ohm's Law$\to$Impurity Levels$\to$Hydrogen Atom$\to$P-n Junction$\to$Deplition Region$\to$Potential Barrier
</footer>
<p>======</p>
<p><Success style="float:center;text-align:center;font-size:28px;" ><B>P-n Junction Basics</B></Success></p>
<p><Primary style="float:center;text-align:center;font-size:24px;"><B>N-Type Semiconductors</B></Primary></p>
<hr>
<main>
<div style='float: left; text-align: left; font-size: 22px; width:100%;'>
<ol start="12">
<li>Though conduction electron concentration or hele concentration changes due to doping, the average charge density remains zero in the material. This is because only neutral atoms are doped.</li>
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<p>Charge density itself = 0</p>
<p>Charged carrier density can be changed</p>
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<div style='float: right; width:0%;'>
<p><img alt="image" src="/subject-images/iitpal/image/physics-class-12-unit-14-chapter-03-p-n-junction-basics-l-3_8-71o6wplux3i-07.jpg"></p>
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</main>
<hr>
<footer style='font-size:18px'>
Semiconductor$\to$<span style="color:blue">N-Type Semiconductors</span>$\to$Drift Velocity$\to$Ohm's Law$\to$Impurity Levels$\to$Hydrogen Atom$\to$P-n Junction$\to$Deplition Region$\to$Potential Barrier
</footer>
<p>======</p>
<p><Success style="float:center;text-align:center;font-size:28px;" ><B>P-n Junction Basics</B></Success></p>
<p><Primary style="float:center;text-align:center;font-size:24px;"><B>N-Type Semiconductors</B></Primary></p>
<hr>
<main>
<div style='float: left; text-align: left; font-size: 22px; width:100%;'>
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<li>
<p>When an electric field is applied in the semiconductor, the electrons and holes move systematically and an electric current is generated</p>
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<p>$I = I_h + I_e,$ the two currents are proportional to the concentiations of the charge carriers</p>
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<p><img alt="image" src="/subject-images/iitpal/image/physics-class-12-unit-14-chapter-03-p-n-junction-basics-l-3_8-71o6wplux3i-08.jpg"></p>
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<hr>
<footer style='font-size:18px'>
Semiconductor$\to$<span style="color:blue">N-Type Semiconductors</span>$\to$Drift Velocity$\to$Ohm's Law$\to$Impurity Levels$\to$Hydrogen Atom$\to$P-n Junction$\to$Deplition Region$\to$Potential Barrier
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