{ "metadata": { "name": "", "signature": "sha256:d284e33c3a44645a717587479459459fbad97c0b83247c27d3e8959966515278" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 2 Transport Phenomena in semiconductors" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.1 Page no 22" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "n=10**20\n", "q=1.6*10**-19\n", "u=800\n", "e=1\n", "\n", "#Calculation\n", "J=n*q*u*e\n", "\n", "#Result\n", "print\"Electron current density is \",J*10**-4,\"*10**4 A/cm**2\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Electron current density is 1.28 *10**4 A/cm**2\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.2 Page no 27" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "Nd=10**12 #/cm**3\n", "ni=10**10 #/cm**3\n", "Nd1=10**18\n", "\n", "#Calculation\n", "import math\n", "n=Nd+math.sqrt(Nd+4*(ni**2))/2.0\n", "n1=Nd1+math.sqrt(Nd1+4*(ni**2))/2.0\n", "\n", "#Result\n", "print\"(a) free electron at 10**12 is \", round(n*10**-12,2),\"*10**12 /cm**3\",\"and hole density is p=9.999*10**7 /cm**3\"\n", "print\"(b) free electron at 10**18 is \",round(n1*10**-18,2),\"*10**18 /cm**3\",\"and hole density is p=10**2 /cm**3\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a) free electron at 10**12 is 1.01 *10**12 /cm**3 and hole density is p=9.999*10**7 /cm**3\n", "(b) free electron at 10**18 is 1.0 *10**18 /cm**3 and hole density is p=10**2 /cm**3\n" ] } ], "prompt_number": 28 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.3 Page no 29" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "K=6.02*10**23 #atoms/mole\n", "b=72.6 #g\n", "c=5.32 #g/cm**3\n", "n=2.5*10**13 #cm**3\n", "q=1.60*10**-19 #C\n", "un=3800 #cm**2/V-s\n", "up=1800 #cm**2/V-s\n", "ni=2.5*10**13\n", "Nd=4.41*10**14\n", "x=1.60*10**-19\n", "n1=4.41*10**22 #electron/cm**3\n", "\n", "#Calculation\n", "C=K*(1/b)*c\n", "A=n*q*(un+up)\n", "R=1/A\n", "p=ni**2/Nd\n", "A1=Nd*x*un\n", "R1=1/A1\n", "A2=n1*x*un\n", "X=A2/A1\n", "\n", "#Result\n", "print\"(a) Concentration of atoms in germanium is \", round(C*10**-22,2) *10**22,\"atoms/cm**3\"\n", "print\"(b) resistivity of intrinsic germanium at 300 degree K is \", round(R,1),\"ohm-cm\"\n", "print\"(c) Resistivity is \", round(R1,2),\"ohm-cm\"\n", "print\"(d) Ratio of conductivity is \",X" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a) Concentration of atoms in germanium is 4.41e+22 atoms/cm**3\n", "(b) resistivity of intrinsic germanium at 300 degree K 44.6 ohm-cm\n", "(c) Resistivity is 3.73 ohm-cm\n", "(d) Ratio of conductivity is 100000000.0\n" ] } ], "prompt_number": 53 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.5 Page no 35 " ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "g=5*10**21\n", "t=2*10**-6 #/cm**3\n", "\n", "#Calculation\n", "p=g*t\n", "\n", "#Result\n", "print\"Hole density in the semiconductor is \", p,\"/cm**3\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Hole density in the semiconductor is 1e+16 /cm**3\n" ] } ], "prompt_number": 56 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.7 Page no 40" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "un=1200 #cm**2/V-s\n", "n0=10.0**18 #/cm**3\n", "ni=10**10 #/cm**3\n", "up=500 #cm**2/V-s\n", "t=2*10**-6 #S\n", "K=5*10**15 #/cm**3\n", "K1=8.620*10**-5 #eV/degree K\n", "q=1.602*10**-19 #C\n", "T=50\n", "Lp=51.0*10**-4\n", "p0=100\n", "Dn=31.2\n", "x=0\n", "\n", "#Calculation\n", "import math\n", "p0=ni**2/n0\n", "Dp=(((K1*T)/q)*up)*10**-18\n", "Jp=((q*Dp)/Lp)*(K-p0)*math.exp(x/Lp)\n", "Lp=math.sqrt(Dp*t)\n", "Jn=-((Dn/Dp)*Jp)*math.exp(x/Lp)\n", "Jn1=((Dn/Dp-1)*Jp)*math.exp(x/Lp)\n", "Jp1=((K*up)/(n0*un))*(Dn/Dp-1)*Jp\n", "\n", "#Result\n", "print\"The drift current density for holes is \", round(Jp1,4),\"exp(-x/Lp)\",\"A/cm**2\"\n", "print\"The diffusion current density for holes is \",round(Jp,2),\"exp(-x/Lp)\",\"A/cm**2\"\n", "print\"The diffusion current density for electrons is \",round(Jn,2),\"exp(-x/Lp)\",\"A/cm**2\"\n", "print\"The drift current density for electrons is \",round(Jn1,2),\"exp(-x/Lp)\",\"A/cm**2\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The drift current density for holes is 0.0058 exp(-x/Lp) A/cm**2\n", "The diffusion current density for holes is 2.11 exp(-x/Lp) A/cm**2\n", "The diffusion current density for electrons is -4.9 exp(-x/Lp) A/cm**2\n", "The drift current density for electrons is 2.79 exp(-x/Lp) A/cm**2\n" ] } ], "prompt_number": 37 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.8 Page no 41" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "ni=1.5*10**10 #/cm**3\n", "Nd=10**18 #/cm**3\n", "Na=10**14\n", "Vt=2.4*10**18\n", "Na1=10**15\n", "Na2=10**16\n", "Na3=10**17\n", "Na4=10**18\n", "Na5=10**19\n", "\n", "#Calculation\n", "import math\n", "V0=Vt*(math.log(Na*Nd)/ni**2)\n", "V01=Vt*(math.log(Na1*Nd)/ni**2)\n", "V02=Vt*(math.log(Na2*Nd)/ni**2)\n", "V03=Vt*(math.log(Na3*Nd)/ni**2)\n", "V04=Vt*(math.log(Na4*Nd)/ni**2)\n", "V05=Vt*(math.log(Na5*Nd)/ni**2)\n", "\n", "#Result\n", "print\"Contact potential across the junction is \"\n", "print round(V0,2),\"\\n\", round(V01,2),\"\\n\" ,round(V02,2),\"\\n\" ,round(V03,2),\"\\n\",round(V04,1),\"\\n\",round(V05,0)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Contact potential across the junction is \n", "0.79 \n", "0.81 \n", "0.84 \n", "0.86 \n", "0.9 \n", "1.0\n" ] } ], "prompt_number": 31 } ], "metadata": {} } ] }