SLIDE 1
Arno Smets
Working Principle of a Semiconductor Based Solar Cell
Excitation of Charge Carriers II
Week 2.3.2
p-Doping
B-
Working Principle of a Semiconductor Based Solar Cell Excitation of - - PowerPoint PPT Presentation
Working Principle of a Semiconductor Based Solar Cell Excitation of - - PowerPoint PPT Presentation
Working Principle of a Semiconductor Based Solar Cell Excitation of Charge Carriers II Week 2.3.2 Arno Smets p-Doping B - Energy band diagram of p-doped Silicon Thermal excitation Conduction Band Acceptor States E Fermi ` Valence Band
SLIDE 2
SLIDE 3
Energy band diagram of p-doped Silicon
Valence Band Conduction Band E Fermi Thermal excitation Acceptor States
`
SLIDE 4
Typical Concentrations: Majority Carriers Minority Carriers = 1016 cm-3 104 cm-3
Si density in c-Si is 5 1022 cm-3
SLIDE 5
Law of Mass Action
Intrinsic material n = p = nintrinsic =1,1X1010cm-3
Doping: At Room Temperature:
n-type doping p0 = n0 = ND
n0 (nintrinsic)2
n0 p0 = (nintrinsic)2 p-type doping n0 = p0 = NA
p0 (nintrinsic)2
n.p=constant
}
n = electron carrier concentration p = hole carrier concentration 1,21X1020 cm-6
SLIDE 6
Example
n-type doping p0 = n0 = ND n0 (nintrinsic )2 n-type doping example p0 = n0 = ND= 1016 cm-3 1,21X1020 1016 = 1,21X104 cm-3
SLIDE 7
Light Absorption scenario 1
Eph = EG:
SLIDE 8
Light Absorption scenario 2
Eph < EG:
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Light Absorption scenario 3
Eph > EG:
SLIDE 10
Light Absorbtion in doped material before light absorption: Majority Carriers Minority Carriers = 1016 cm-3 104 cm-3
SLIDE 11
Light Absorbtion in doped material 1011 now electron-hole pairs: 104 + 1011 cm-3 Majority Carriers Minority Carriers = 1016 + 1011 cm-3
SLIDE 12
Temperature
- 0,5
EC E F(E) EF EV
- P+
Doping Light
SLIDE 13