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{
"metadata": {
"name": "CH18"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 18 : Electrical Properties"
]
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 18.1 Page No 682"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Computation of the Room-Temperature Intrinsic Carrier Concentration for Gallium Arsenide\n",
"\n",
"#Given\n",
"sigma=10**-6 # (Ohm-m)**-1 Electrical Conductivity\n",
"e=1.6*10**-19 #Coulomb Charge on electron\n",
"m_e=0.85 # m**2/V-s Mobility of electron\n",
"m_h=0.04 # m**2/V-s Mobility of holes\n",
"\n",
"#Calculation\n",
"#ni is Intrinsic carrier concentration\n",
"ni=sigma/(e*(m_e+m_h))\n",
"\n",
"print\"Intrinsic Carrier Concentration is\",round(ni,-11),\"m**-3\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Intrinsic Carrier Concentration is 7e+12 m**-3\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 18.2 Page No 689"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Electrical Conductivity Determination for Intrinsic Silicon at 150\u00b0C\n",
"\n",
"#Given\n",
"e=1.6*10**-19 #Coulomb Charge on electron\n",
"ni=4*10**19 #For Si at 423 K (m**-3)\n",
"#Values of m_e and m_h are deduced from graphs at page No.689\n",
"m_e=0.06 #m**2/V-s Mobility of electron\n",
"m_h=0.022 #m**2/V-s Mobility of holes\n",
"\n",
"#calculation\n",
"#sigma is electrical conductivity\n",
"sigma=ni*e*(m_e+m_h)\n",
"\n",
"#result\n",
"print\"Electrical Conductivity is \",round(sigma,2),\"(ohm-m)**-1\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Electrical Conductivity is 0.52 (ohm-m)**-1\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 18.3 Page No 690"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Room-Temperature for Extrinsic Silicon\n",
"\n",
"#Given (b)\n",
"n=10**23 #m**-3 Carrier Concentration\n",
"e=1.6*10**-19 #Coulomb Charge on electron\n",
"#From graph 18.18 m_e is calculated corresponding to n=10**23\n",
"m_e=0.07 #m**2/V-s Mobility of electron\n",
"\n",
"#Calculation\n",
"#For extrinsic n-type, the formula used is:\n",
"sigma=n*e*m_e\n",
"\n",
"\n",
"#(c)Elevated-Temperature Electrical Conductivity Calculations for Extrinsic Silicon\n",
"#From graph 18.19a m_e2 is calculated corresponding to 373 K\n",
"m_e2=0.04 #m**2/V-s Mobility of electron\n",
"sigma2=n*e*m_e2\n",
"\n",
"#Result\n",
"print\"Conductivity at n=10**23 is \",sigma,\"(Ohm-m)**-1\"\n",
"print\"Conductivity at T=373 K becomes \",sigma2,\"(Ohm-m)**-1\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Conductivity at n=10**23 is 1120.0 (Ohm-m)**-1\n",
"Conductivity at T=373 K becomes 640.0 (Ohm-m)**-1\n"
]
}
],
"prompt_number": 9
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Design Example 18.1, Page No: 691"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Specify an impurity acceptor type\n",
"\n",
"#Given\n",
"c=50 #ohm**-1, room temprature conductivity\n",
"Na1=10**22 #m**-3, assumed impurity content value\n",
"mu1=0.04 #m**2/Vs, assumed electrical mobility\n",
"e=1.6*10**-19 #Electronic charge\n",
"NA=6.023*10**23 #Avagadro no\n",
"\n",
"#Calculation\n",
"C=Na1*e*mu1 #Conductivity\n",
"#Decreasing an impurity content\n",
"Na2=10**21 #m**-3, \n",
"mu2=0.045 #m**2/Vs,\n",
"C=Na2*e*mu2\n",
"#So we get conductivity = 50 at\n",
"Na=8*10**21 \n",
"#For Silicon\n",
"rho=2.33 # g/cm**3\n",
"Asi=28.09 # g/mole\n",
"Nsi=(NA*rho*10**6)/(Asi)\n",
"Ca=(Na/(Na+Nsi))*100\n",
"\n",
"#Result\n",
"print\"The concentration of acceptor impurities is\",round(Ca,7)\n",
"print\"Thus a Silicon material having conductivity 50 ohm**-1 \\nmust contain\",round(Ca,7),\"% boron,aluminium,Gallium or indium .\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The concentration of acceptor impurities is 1.6e-05\n",
"Thus a Silicon material having conductivity 50 ohm**-1 \n",
"must contain 1.6e-05 % boron,aluminium,Gallium or indium \n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 18.4 Page No 693"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Hall Voltage Computation\n",
"\n",
"#Given\n",
"sigma=3.8*10**7 #(Ohm-m)**-1 Electrical Conductivity\n",
"m_e=0.0012 #m**2/V-s Mobility of electron\n",
"Rh=-m_e/sigma #Hall coefficient\n",
"Ix=25 #Ampere(A) Current\n",
"d=15*10**-3 #m Thickness\n",
"Bz=0.6 #Tesla Magnetic field\n",
"\n",
"#Calculation\n",
"Vh=Rh*Ix*Bz/d\n",
"\n",
"#Result\n",
"print\"Hall coefficient is \",round(Rh,13),\"V-m/A-Tesla\"\n",
"print\"Hall Voltage is \",round(Vh,10),\"V\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Hall coefficient is -3.16e-11 V-m/A-Tesla\n",
"Hall Voltage is -3.16e-08 V\n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 18.5 Page No 707"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#find the Capacitance \n",
"\n",
"#Given\n",
"A=6.45*10**-4 #m**2, area\n",
"d=2*10**-3 #m. Plate separation\n",
"V=10 #V Potential\n",
"Er=6 #Dielectric constant\n",
"Eo=8.85*10**-12 #F/m Constant dielectric constant\n",
"#Calculation\n",
"E=Er*Eo\n",
"C=E*A/d\n",
"Q=C*V\n",
"D=E*V/d\n",
"P=D-Eo*V/d\n",
"\n",
"#Result\n",
"print\"The Capacitance is\",round(C,13),\"F\"\n",
"print\"The magnitude of charge stored is \",round(Q,12),\"C\"\n",
"print\"The Dielectric displacement is is\",round(D,9),\"C/m**2\"\n",
"print\"The Polarization is\",round(P,9),\"C/m**2\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The Capacitance is 1.71e-11 F\n",
"The magnitude of charge stored is 1.71e-10 C\n",
"The Dielectric displacement is is 2.65e-07 C/m**2\n",
"The Polarization is 2.21e-07 C/m**2\n"
]
}
],
"prompt_number": 15
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}
|
