(a) Why does one expect a p-n junction GaAs solar cell to have higher power conv
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Question
(a) Why does one expect a p-n junction GaAs solar cell to have higher power conversion efficiency than a p-n junctionssolar cel? Silicem (b)List one advantage of a p-i-n junction solar cell over a p-n junction solar cell Diffusion lengths of holes in a n-type semiconductor (S) and for electrons in () the p-type semiconductor (S) are 8 micrometers and 2 micrometers respectively. Absorption co-efficient, has a value of 10' cm. In homDjundon designing asolar cel from this material, the total thickness of semiconductor, S should be, (i) in the (2-8) micrometers range, (i) in the (10-20) micrometers range, (ii) at least 100 micrometers. Explam bnExplanation / Answer
a) SIlicon solar cells have indirect bandgap while GaAs has direct bandgap due to which the P-N Junction GaAs Solar Cell has a higher efficiency. Direct Bandgap is directly proportional to fill factor, the power conversion efficiency, the optimum device length and the spectrum of the quantum efficiency.
b) Due to the Wider Intrinsic region compared to that of PN Junction Diode, PIN diode is suitable for attenuators, fast switches, photodetectors, and high voltage power electronics applications.
C)
i) Definitely not as the addition of two diffusion lengths is 10 micrometers.
Compared to ii and iii, 100 micrometers thickness provides better absorption coefficient. Absorption Coefficient is directly proportional to THickness. So, as thickness increases, it can absorb more photons to generate power. Thus, increasing the overall efficiency of the Solar Cell.
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