tailieunhanh - Solar Cells Silicon Wafer Based Technologies Part 3

Tham khảo tài liệu 'solar cells silicon wafer based technologies part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Epitaxial Silicon Solar Cells 41 specific boundary conditions when the device is operated under short circuit concerning the grain boundary recombination velocity in the active layer Sng and the effective back surface recombination velocity Seff at the low high junction. The simplified relation gives the expression for effective electron recombination velocity Seff as a function of the material s doping concentration of the active layer and the substrate Na Na assumed constant all over of these regions bulk . Moreover the grain boundary recombination velocity in the front and the active layer is considered the same and symbolized as Sgb. The solution of the continuity equations 14 and 16 is obtained in analytical form using the Green s function method. This procedure is briefly described in kotsovos. K Perraki. V 2005 . The analytical expression of the front layer photocurrent density Jp is derived by differentiating the hole density distribution in the junction edge region z d1-wn presented in the form of infinite series Halder. Williams. T. R. 1983 Jp x y 2 4qaF X Ă LpeffM- y sin mXg sin nYg . A cos mx cos nv mn mn a2L2pfff -1 Np aLpeff - exp -a d1 - wn Np cosh d1 Wn sinh 111 Wn X _ pf__ pf d-1 Wn d- Wn Np sinh -1------n cosh -1---n Lpeff Lpeff -aLpeff exp - d1 - Wn 17 where the variables x and y represent arbitrary points inside the grain and Mx Ny Lf Np are expressed by proper equations as functions of Spg Dp Xg Yg Lp and SF. In a similar way the analytical expression of the base region photocurrent density Jn is given in the form of infinite series by differentiating the electron density distribution in the junction edge region z d2 -Wp by the relation Jn 4qaFe-a d1 Wp X LmffK2L2 sin kXg sin lYg k l cos kx cos ly kl a2L2neff - 1 d Nn lcoslli X aLneff------------------- Wp - e-a d2-Wp neff sinh d2- Wp- .pỴ ---Wp Lneff _ d2 -W _ d2 -W Nn sinh p cosh p Lneff .