{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 17: Band Theory of Solids" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 17.1, Page 17.18" ] }, { "cell_type": "code", "collapsed": false, "input": [ " \n", "# Given \n", "a = 3e-10 # side of square lattice in m\n", "h = 6.62e-34 # Planck constant in J sec\n", "e = 1.6e-19 # charge on an electron in C\n", "m = 9.1e-31 # mass of electron in kg\n", "\n", "#Calculations\n", "p = (h / (2 * a))\n", "E = (p**2 / (2 * m)) * (1. / e)\n", "\n", "#Result\n", "print \"Electron momentum value at the sides of first Brilloin zone is %.1e kg-m/sec\\nEnergy of free electron is %.1f eV\"%(p,E)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Electron momentum value at the sides of first Brilloin zone is 1.1e-24 kg-m/sec\n", "Energy of free electron is 4.2 eV\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 17.2, Page 17.19" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import log,pi\n", "\n", "# Given \n", "n = 5e22 # no. of atoms per m^3\n", "t = 300 # room temperature in K\n", "k = 1.37e-23 # Boltzmann's constant in J/K\n", "h = 6.62e-34 # Planck constant in J sec\n", "e = 1.6e-19 # charge on an electron in C\n", "m = 9.1e-31 # mass of electron in kg\n", "\n", "#Calculations\n", "d = (k * t) * log(n * h**3 / (2 * (2 * pi * m * k * t)**(3./2)))\n", "\n", "#Result\n", "print \"Position of fermi level is %.3f eV\"%(-d/e)\n", "#Answer varies due to round-off errors" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Position of fermi level is 0.159 eV\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 17.3, Page 17.19" ] }, { "cell_type": "code", "collapsed": false, "input": [ " \n", "# Given \n", "E = 0.3 # Fermi energy in eV\n", "T = 330 # temperature in K\n", "t = 300 # room temperature in K\n", "k = 1.37e-23 # Boltzmann's constant in J/K\n", "h = 6.62e-34 # Planck constant in J sec\n", "e = 1.6e-19 # charge on an electron in C\n", "m = 9.1e-31 # mass of electron in kg\n", "\n", "#Calculations\n", "d = (T / t) * (E)\n", "\n", "print \"New position of fermi level is %.2f eV\"%d" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "New position of fermi level is 0.30 eV\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 17.4, Page 17.20" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import *\n", "\n", "# Given\n", "E = 0.7 # band gap for semiconductor in eV\n", "t = 300 # room temperature in K\n", "k = 1.38e-23 # Boltzmann's constant in J/K\n", "h = 6.62e-34 # Planck constant in J sec\n", "e = 1.6e-19 # charge on an electron in C\n", "m = 9.1e-31 # mass of electron in kg\n", "\n", "#Calculations\n", "n = 2 * ((2 * pi * k * t * m) / h**2)**(3./2) * exp(-(E * e / (2 * k * t)))\n", "\n", "#Result\n", "print \"Density of holes and electron is %.1e per m^3\"%n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Density of holes and electron is 3.4e+19 per m^3\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 17.5, Page 17.20" ] }, { "cell_type": "code", "collapsed": false, "input": [ " \n", "# Given \n", "n = 5e28 # no. of atoms in per m^3\n", "e = 1.6e-19 # charge on an electron in C\n", "\n", "#Calculations\n", "R = -(1 / (n * e))\n", "\n", "#Resilt\n", "print \"Hall coefficient is %.3e m^3/C\"%R" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Hall coefficient is -1.250e-10 m^3/C\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 17.6, Page 17.20" ] }, { "cell_type": "code", "collapsed": false, "input": [ " \n", "# Given \n", "a = 4.28e-10 # cell side of Na in m\n", "e = 1.6e-19 # charge on an electron in C\n", "\n", "#Calculations\n", "n = (2 / a**3)\n", "R = -(1 / (n * e))\n", "\n", "#Result\n", "print \"Hall coefficient is %.3e m^3/C\"%R" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Hall coefficient is -2.450e-10 m^3/C\n" ] } ], "prompt_number": 7 } ], "metadata": {} } ] }