{
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{
"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": {}
}
]
}