Surface and bulk passivation of multicrystalline silicon solar cells by ...

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89 alloying results in metallization "spikes," which are formed at the defect-cluster site. They result in increased shunting (lower shunt resistance) of the cell. Thus, the calculated FF in Table 5.1 is higher than the measured FF. The entire I-V plot of each cell can also be calculated by this theory. Figure 5.6 compares calculated I-V characteristics of cells A, C, and the one without defects. It is seen that a dominant effect of defect clusters is in degrading the voltage-related parameters [112]. Figure 5.6 A comparison of calculated I-V characteristics of three cells---cell #113, cell #107, and cell having no defects [112]. This model can also be used to provide an in-depth understanding of the cell operation, because it provides complete spatial distribution of voltage and currents for any terminal voltage. As an example, Figure 5.7 shows the current flow in various regions of cell #108 at different voltages. Here, the light (green) color implies a current generation and the dark (red) color, a current flow in the opposite direction, depicting an internal dissipation. Notice that the device is generating current until it reaches a voltage
90 of 0.5 V. At a terminal voltage of 0.505 V and above, the device is actually dissipating power in the regions of defect clusters. A comparison of Figure 5.7 with Figure 5.5 shows that the dissipation regions correspond to the defect clusters. Terminal voltage 0.5 V Terminal voltage 0.505V Terminal voltage 0.515 V Terminal voltage 0.525V Figure 5.7 The current flow in various regions of cell #108 at different voltages [112]. A combination of theory and experiment was used to determine the loss in the efficiency of a me-Si solar cell due to defect clusters. Several salient results of this analysis are:
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Copyright Warning & Restrictions Th
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ABSTRACT SURFACE AND BULK PASSIVATI
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SURFACE AND BULK PASSIVATION OF MUL
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APPROVAL PAGE SURFACE AND BULK PASS
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Chuan Li, B.L. Sopori, P. Rupnowski
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ACKNOWLEDGEMENT The work presented
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TABLE OF CONTENTS (Continued) Chapt
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LIST OF TABLES Table Page 2.1 Posit
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LIST OF FIGURES (Continued) Figure
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LIST OF FIGURES (Continued) Figure
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2 percent; however, soon, more adva
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4 Figure 1.1 World solar module pro
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6 bond is called a hole. It too can
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8 Figure 1.4 The I-V characteristic
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10 First generation cells consist o
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12 Basically, materials for manufac
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14 Defects are generally categorize
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16 copper, or nickel in concentrati
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18 the SiNx:H layer during the ther
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CHAPTER 2 SILICON NITRIDE LAYER FOR
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22 reflectance of polished Si can b
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24 information is application-orien
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26 film fed growth (EFG) ribbon sil
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28 Figure 2.5 Deposition of SiΝ :
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30 Figure 2.6 shows the dependence
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32 atoms, the interface states are
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34 2.5 Bulk Passivation of Si by Si
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36 It was found that the bulk lifet
Page 57 and 58: CHAPTER 3 MODELING OF SURFACE RECOM
Page 59 and 60: 40 Figure 3.2 Schematic diagram of
Page 61 and 62: 42 σ and σp are the capture cross
Page 63 and 64: 44 Qsi — charge density induced i
Page 66 and 67: 47 Figure 3.5 The calculated depend
Page 68 and 69: 49 * 10 Λ m; m is in a range from
Page 70 and 71: 51 Na, sigma_n, sigma_p: enter x.xx
Page 72 and 73: 53 Figure 3.7 Measured Seff(Δn) de
Page 74 and 75: 55 curves converge to a single valu
Page 76 and 77: 57 seen that, initially Ss decrease
Page 78 and 79: 59 carrier recombination within the
Page 80 and 81: 61 recombination in the SCR influen
Page 82 and 83: 63 Figure 3.13 shows that: 1) after
Page 84 and 85: CHAPTER 4 MINORITY-CARRIER LIFETIME
Page 86 and 87: 67 Figure 4.1 Α photograph of QSSP
Page 88 and 89: 69 work. The most convenient is 1 m
Page 90 and 91: 7Ι dependence of the minority carr
Page 92 and 93: 73 It was tempting to assume that l
Page 94 and 95: 75 resistivities and lifetime) do n
Page 96 and 97: 77 5.2 Objective An electronic mode
Page 98 and 99: 79 Figure 5.2 is a photograph of a
Page 100 and 101: 81 impurity-gettering methods which
Page 102 and 103: 83 distribution of local currents a
Page 104 and 105: 85 modeling. Wafers were selected f
Page 106 and 107: 87 Figure 5.5 A comparison of (a) d
Page 110 and 111: 91 (i) Defect clusters are the prim
Page 112 and 113: 93 SiNX induced charge density on t
Page 114 and 115: APPENDIX I PROGRAMS TO CALCULATE SR
Page 116 and 117: 97 phin = -ΕΙ - 1 / beta * log(nd
Page 118 and 119: 99 ίter3 = 0 for xi=1 to nmax/2-1
Page 120 and 121: 101 input "output file name {XXXXXX
Page 122 and 123: 103 F (i) = (exp (beta * (phip - ph
Page 124 and 125: APPENDIX III COMPUTATIONAL METHOD F
Page 126 and 127: 107 where, dscr is the width of the
Page 128 and 129: REFERENCES 1. E. Becquerel , C. R.
Page 130 and 131: 44. L.L. Alt, S.W. Ing. Jr. and K.W
Page 132 and 133: 90. B.L. Sopori, Y. Zhang, and N.M.
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