## Solutions to Selected Problems Exercise 2.1

N 4 N (a) Energy at earth’s mean distance/unit area/unit time = (rs/des)2 energy at sun’s surface/unit area/unit time = (rs/deS)2 OTs4 Projected area of earth = nre2 Surface area of earth = 4nre2 Incoming energy = outgoing energy (rs/des)2 oTs4nre2 = oTe44nre2 Te = Ts (rs/des)1/2/21/2 = 289.38 K (b) Trick Question! The earth […]

## Quasi-Fermi Levels E.1 Introduction

The concept of a fermi level was introduced in Chap. 4 to describe the energy distribution of electrons and holes in thermal equilibrium. In non-equilibrium, quasi-fermi levels or imrefs provide a useful tool for semiconductor device analysis as outlined below. Formally, they correspond to the electrochemical potentials of non-equilibrium thermodynamics. E.2 Thermal Equilibrium A system […]

## . C.5 More General Integrals

For integral j, this has a finite (J + 1) number of non-zero terms and the integral simplifies to: For example, в (п, є) = £3в) (п-є)/6 + є2Р1(ц-є)/2 + £/?2 (п-є) + в (п-є) (C.22) where each term on the right can be evaluated using Eq. (C.16). The inverse of such a function for […]

## C.4 Approximate Expressions

Considerable effort has been invested in deriving approximate expressions for Fermi-Dirac integrals as reviewed elsewhere (Blakemore 1982). One compact approximation for negative arguments is based on the following expression: 2-(j+1) <> C± <>±(1II±(0)-1) will give the best results for negative arguments, where the value on the right is ensures that the expression gives the correct […]

## Fermi-Dirac and Bose-Einstein Integrals

C.1 Functional Expressions Fermi-Dirac integrals of the form occur widely in semiconductor transport theory and carrier density calculations, where E is the energy above the edge of the respective band normalised by the thermal energy kT and n is a similarly normalised value of the carrier fermi – energy or electrochemical potential. Г(п) is the […]

## Physical Constants

Symbol Definition V alue* q electronic charge 1.602176462(63) x 10-19C m0 electron rest mass 9.10938188(72) x 10-28g 9.10938188(72) x 10-31 kg П circle circumference to diameter (calculable) 3.14159265358979… c velocity of light in vacuum (exact value) 2.99792458 x 1010 cm/s 2.99792458 x 108 m/s £o permittivity of vacuum (exact value) 8.854187817.. . x 10-14 F/cm […]

## Conclusions

From the analysis of this book, it appears that there are sufficient options for improving the performance of solar photovoltaic cells beyond the single junction limits, that greatly improved performance, at some stage in the future, is very likely. The tandem cell approach of Chap. 5 already demonstrates that such enhanced performance is feasible. Cell […]

## Without Filter

If the filter is removed, the analysis parallels that of the previous section with Eq. (9.18) remaining valid. However, the simplification made possible by Eqs. (9.19) and (9.20) no longer apply. Instead, the equivalent of Eq. (9.21) becomes: Where E h/N h, N c/N h and Ec/E h are given by the same expressions as […]