태양전지공학 - contents.kocw.net

1 Chapter 2 x SemiconductorPhotonfluxinPhotonfluxoutIo I(x)I(x)-dIdxxSemiconductorPhotonfluxinP hotonfluxoutIoI(x)I(x)-dIdxx Chapter 2 (Intensity) Io , I(x) x , I [ ] x x . (absorption coefficient)xIIdad-=xIIdda-=)exp()(0xIxI a-= Chapter 2 103cm-1 104cm-1 70%, 50%, 10%, . 103cm-1 104cm-1 , x .)exp()(0xIxIa-=0)(n11 IxIx -= m69 m46 m1% m23 m10% m50% m70%x( 104cm-1)x( 103cm-1)I(x)/Io 104cm-1 m ,, 103cm-1 69 m .. Chapter 2 Chapter 2 + (eV) (nm)1s (2 )2s (2 )3s (2 )2p (6 )3p (2 )KLMKLM ( )+ (eV) (nm)1s (2 )2s (2 )3s (2 )2p (6 )3p (2 )KLMKLM ( ) Chapter 2 (energy band) Chapter 2 Chapter 2.

2 ( , ) .. , . Chapter 2 104cm-1 . 1:1 ,, joule eV . ,, n=g . Si =10-7sec .. p- 25 C Iv(x)=50 mW/cm2 = m, =10-7sec . ) )( () )( ()(' = == )10)( ( = =D-n Chapter 2 n- p- 5+n- 3-p- Acceptor ionDonor ion5+5+n- 3-3-p- Acceptor ionDonor ion Chapter 2p-n -eNaeNdxB-h+pnAs+ -WpWn -WpWnEoMrnetE(x)VoV(x)xx0 EoMWn-Wp n- p- p-n -eNaeNdxB-h+pnAs+ -WpWn -WpWnEoMrnetE(x)VoV(x)xx0 EoMWn-Wp n- p- p-n Chapter 2.

3 A B . x = pn( )= 0 ,,B= 0 . x=0 pn= pn(0) A= pn(0) . x ( ) ( ) . n- pn(x) . , Lh . + =DhhnLxBLxAxpexp-exp)( D=DhnnLxpxp-exp)0()( Chapter 2n p Na Nd p+n . Q ( ) Q=eNaWp=eNdWn n . Nd Na . p 1018cm-3 n 1016cm-3 p-n ? 2/1002w =deNVe Chapter 2 . Nd=1016cm-3=1022m-3,,Vo= ,, r= Wo . ( 99%) n . ) ()10)((10V) (n12101618020= = =VnNNekTVida )10)( () )( )( (2272/12219122/100me --- = = =deNVW Chapter 2 Chapter 2 Chapter 2 - VVIIVVIIVVIIILL ightVVIIILL ight(a) (b) Chapter 2 - - VOCISC - VOCISC Chapter 2 : R( :) : F( :) : ~ + d AM (air mass) AM.

4 B0: b : Z : (open-circuit voltage)llhlllllllmlmdqFRdJdJIcomscmscsc )()())(1()()( @= ZbbAMsec0=]1)/[(10+=IInqnkTVscoc Chapter 2 Jsc(mAcm-2) Voc(V)SiGoAs6070 Jsc(mAcm-2) Voc(V)SiGoAs6070 Chapter 2 .. p-n .Na = 5x1018cm-3 Nd= 1016cm-3Dn= 25cm2/sec Dp= 10cm2/sec 0 = 5x10-7sec p0 = 10-7sec JL= IL/A = 15mA/cm2 . += +== )105)(25( )105)(25(7070mtmt= === ==--nppnnnDLDL Chapter 2 ..21116418410190 )10)(1010(10)105)( (252) )( (cmAJ---- = + = ) (n1) ()1(n1)1(11300= +=+=+=--JJqkTIIqkTVLLoc Chapter 2 (Fill Factor, FF) - - -= =1exp1exp1 FFnkTqVnkTqVVVVIVI mmocmocscmm1) (1 FFoc++-=ococuuu.

5 Chapter 2 Current,PowerVoltageCell with Low Fill FacterVOC(Vmp, Imp)Vmp, PmaxArea A is smallerFor lower FFAISCBC urrent,PowerVoltageCell with High Fill FacterVOC(Vmp, Imp)Vmp, PmaxAISCBFF=Imp*VmpIsc*Voc= area Aarea BCurrent,PowerVoltageCell with Low Fill FacterVOC(Vmp, Imp)Vmp, PmaxArea A is smallerFor lower FFAISCBC urrent,PowerVoltageCell with High Fill FacterVOC(Vmp, Imp)Vmp, PmaxAISCBFF=Imp*VmpIsc*Voc= area Aarea B(a) (b) Chapter 2 (efficiency) . PmaxPmax= Vm Im . , FF = ==inputscocinputmminputmPJVPVIPPh Chapter 2 ` Passivation Passivation pn ` Passivation Passivation pn Chapter 2 Chapter 2.

6 0 .. l= . 0 .. l=hcEgl= Chapter 2 QEhcqSRl= Chapter 2 Chapter 2 npnp Chapter 2 R6R7 R2R3R8R5R4R1p- n- R6R7 R2R3R8R5R4R1p- n- Chapter 2 PN Back Surface Reflector Impurity Control Tandem, Superlattice Quantum well AR Coating Light Trapping Metallization Back Surface Field Doping Concentration Cell Surface Passivation Gettering Point Contact Doping Metallization Leakage Current33304455991000010095534225241914 hv>Eg hv<Eg ( ) ( ) Chapter 2 010020030040050060015161718192021 Sr=100 cm/s Sr=1000 cm/s Sr=10000 cm/sEfficiency ( % ) Diffusion length ( Chapter 2 IQE Chapter 2 , , Chapter 2 , , IQE Chapter 2)