{
"metadata": {
"name": "",
"signature": "sha256:265535ddaffc0266824860d662b8052593e36ca515dd70e32c070b51cf842e7d"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter18-Semiconductors"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex2-pg539"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"##Example 18.2\n",
"##calculation of probability\n",
"\n",
"##given values\n",
"T=300.;##temp in K\n",
"kT=.026;##temperture equivalent at room temp in eV\n",
"Eg=5.6;##forbidden gap in eV\n",
"\n",
"##calculation\n",
"f=1./(1.+math.e**(Eg/(2.*kT)));\n",
"\n",
"print'%s %.3e %s'%('probability of an e being thermally promoted to conduction band is',f,'');\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"probability of an e being thermally promoted to conduction band is 1.698e-47 \n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex3-pg540"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"##Example 18.3\n",
"##calculation of fraction of e in CB\n",
"\n",
"##given values\n",
"T=300.;##temp in K\n",
"kT=.026;##temperture equivalent at room temp in eV\n",
"Eg1=.72;##forbidden gap of germanium in eV\n",
"Eg2=1.1;##forbidden gap of silicon in eV\n",
"Eg3=5.6;##forbidden gap of diamond in eV\n",
"\n",
"##calculation\n",
"f1=math.e**(-Eg1/(2.*kT));\n",
"print'%s %.6f %s'%('fraction of e in conduction band of germanium is',f1,'');\n",
"f2=math.e**(-Eg2/(2.*kT));\n",
"print'%s %.3e %s'%('fraction of e in conduction band of silicon is',f2,'');\n",
"f3=math.e**(-Eg3/(2*kT));\n",
"print'%s %.3e %s'%('fraction of e in conduction band of diamond is',f3,'');\n",
"print'abpove results shows that larger the band gap and the smaller electrons that can go under into the conduction band'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"fraction of e in conduction band of germanium is 0.000001 \n",
"fraction of e in conduction band of silicon is 6.501e-10 \n",
"fraction of e in conduction band of diamond is 1.698e-47 \n",
"abpove results shows that larger the band gap and the smaller electrons that can go under into the conduction band\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex4-pg540"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"##Example 18.4\n",
"##calculation of fractionional change in no of e\n",
"\n",
"##given values\n",
"T1=300.;##temp in K\n",
"T2=310.;##temp in K\n",
"Eg=1.1;##forbidden gap of silicon in eV\n",
"k=8.6*10**-5.;##boltzmann's constant in eV/K\n",
"\n",
"##calculation\n",
"n1=(10**21.7)*(T1**(3/2.))*10**(-2500.*Eg/T1);##no of conduction e at T1\n",
"n2=(10**21.7)*(T2**(3/2.))*10**(-2500.*Eg/T2);##no of conduction e at T2\n",
"x=n2/n1;\n",
"print'%s %.1f %s'%('fractional change in no of e is',x,'');\n",
"print 'in book he just worte ans but he didnt calculated final ans but here is i calculated'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"fractional change in no of e is 2.1 \n",
"in book he just worte ans but he didnt calculated final ans but here is i calculated\n"
]
}
],
"prompt_number": 17
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex5-pg541"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"##Example 18.5\n",
"##calculation of resistivity\n",
"\n",
"##given values\n",
"e=1.6*10**-19;\n",
"ni=2.5*10**19;##intrinsic density of carriers per m**3\n",
"ue=.39;##mobility of e \n",
"uh=.19;##mobility of hole\n",
"\n",
"\n",
"##calculation\n",
"c=e*ni*(ue+uh);##conductivity\n",
"r=1/c;##resistivity\n",
"print'%s %.2f %s'%('resistivity in ohm m is',r,'');"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"resistivity in ohm m is 0.43 \n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex6-pg548"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"##Example 18.6\n",
"##calculation of conductivity of intrinsic and doped semiconductors\n",
"\n",
"##given values\n",
"h=4.52*10**24;##no of holes per m**3\n",
"e=1.25*10**14;##no of electrons per m**3\n",
"ue=.38;##e mobility\n",
"uh=.18;##hole mobility\n",
"q=1.6*10**-19;##charge of e in C\n",
"##calculation\n",
"ni=math.sqrt(h*e);##intrinsic concentration\n",
"ci=q*ni*(ue+uh);\n",
"print'%s %.2f %s'%('conductivity of semiconductor(in S/m) is',ci,'');\n",
"cp=q*h*uh;\n",
"print'%s %.2f %s'%('conductivity of doped semiconductor (in S/m) is',cp,'');"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"conductivity of semiconductor(in S/m) is 2.13 \n",
"conductivity of doped semiconductor (in S/m) is 130176.00 \n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex7-pg548"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"##Example 18.7\n",
"##calculation of hole concentration\n",
"\n",
"##given values\n",
"ni=2.4*10**19.;##carrier concentration per m**3\n",
"N=4*10**28.;##concentration of ge atoms per m**3\n",
"\n",
"##calculation\n",
"ND=N/10**6.;##donor cocntrtn\n",
"n=ND;##no of electrones\n",
"\n",
"p=ni**2./n;\n",
"print'%s %.3e %s'%('concentartion of holes per m^3 is',p,'');"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"concentartion of holes per m^3 is 1.440e+16 \n"
]
}
],
"prompt_number": 18
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex8-pg558"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"##Example 18.8\n",
"##calculation of Hall voltage\n",
"\n",
"##given values\n",
"ND=10**21.;##donor density per m**3\n",
"B=.5;##magnetic field in T\n",
"J=500.;##current density in A/m**2\n",
"w=3*10**-3.;##width in m\n",
"e=1.6*10**-19.;##charge in C\n",
"\n",
"##calculation\n",
"\n",
"\n",
"V=B*J*w/(ND*e);##in volts\n",
"print'%s %.2f %s'%('Hall voltage in mv is',V*10**3,'');"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Hall voltage in mv is 4.69 \n"
]
}
],
"prompt_number": 14
}
],
"metadata": {}
}
]
}