Glossary – Latin symbols

Variable (Usual)

Dimension Meaning

A_ARC Absorption in the anti reflectance coating

A_i m² Area of the region with emitter sheet resistance R_sheet,i

A_max m² Not-metalized solar cell area

A_shaded m² Area, which is additionally shaded

A_total m² Area of the whole solar cell or symmetry element

B cm³s^-1 Coefficient of radiative recombination Cloc

Calibration factor needed for voltage calibration of PL-measurements

C_n m⁶/s Auger coefficient of the eeh process C_p m⁶/s Auger coefficient of the ehh process

df m Distance of two adjacent fingers on the front of a solar cell

D_it cm^-2 Surface or interface state density

d_n m Depth of one node in direction parallel to the fingers in a distributed circuit model

Dn cm²s^-1 Diffusion coefficient of the electrons D_p cm²s^-1 Diffusion coefficient of the holes

E V/m Electrical field

E_C eV Lowest energy in the conduction band

EF eV Fermi level

E_g eV Energy of the band gap

E_i eV Energy of the fermi level in an intrinsic semiconductor at thermal equilibrium

Ek eV Energy of an electron with momentum k

E_t eV Energy of a defect level

E_top eV Highest energy in the conduction band

Variable (Usual)

Dimension Meaning

EV eV Highest energy in the valence band

F(E) Fermi-Dirac distribution

f_E Emitter correction factor to correct the effect of the emitter sheet resistance in a distributed circuit model fF

Correction factor to correct the effect of the resistance of the metal fingers in a distributed circuit model

G m^-3s^-1 Generation rate

G_ill m^-3s^-1 Generation rate due to illumination G_n m^-3s^-1 Generation rate of electrons

Current, which passes the emitter resistance Rl* in between two adjacent fingers in a distributed circuit model of a solar cell

Iwith shading W/cm²

Illumination intensity used to generate the one sun short circuit current density in case of an additionally shaded area

Iwithout shading W/cm²

Illumination intensity used to generate the one sun short circuit current density without additionally shaded region (0.1 W/cm²)

J0 A/cm² Generation current density (one diode model) J₀₁ A/cm² Generation current density in the neutral regions

(two diode model)

J₀₂ A/cm² Generation current density of the space charge region (two diode model)

Jill A/cm² Additionally generated current density due to illumination

( )

^V

J_local^{xsuns A/cm2} Local IV characteristic of a solar cell illuminated with an illumination intensity of x suns

Variable (Usual)

Dimension Meaning

Jmpp A/cm² Current density at maximum power point Jn A/cm² Current density of the electrons

J_p A/cm² Current density of the holes Jsc A/cm² Short circuit current density

xsuns local

Jsc_, A/cm² Local short circuit current density using an illumination intensity of x suns

sun

Jsc^{1 A/cm2} One sun short circuit current density

k kg m s^-1 Momentum of an electron

kB Boltzmann constant, 1.380 6504×10^-23 J/K [117]

l_f cm Length of one finger on a solar cell

Ln cm Diffusion length of the electrons

Lh cm Diffusion length of the holes

m Ideality factor used in the one diode model

M

Part of the area of the solar cell, which is illuminated by the measurement spot and which is covered by the front metallization

MC Number of equivalent minima in the conduction band

m_de kg Density-of-state effective mass for electrons m_dh kg Density-of-state effective mass for holes

mhh* kg Effective mass of the heavy holes in the valence band m_i* kg Effective mass of the electrons along the principal

axes of the ellipsoidal energy surfaces

m_lh* kg Effective mass of the light holes in the valence band

mloc Local ideality factor

n cm^-3 Electron density in the conduction band

Ν(Ε) cm^-3 Density of states

n₀ cm^-3 Electron concentration in the conduction band at thermal equilibrium

n₁ cm^-3 SRH density for electrons

Variable (Usual)

Dimension Meaning

n₁ Ideality factor of the first diode in the two diode model

n₂ Ideality factor of the second diode in the two diode model

N_A cm^-3 Total concentration of acceptors

−

NA ^cm-3 Concentration of ionized acceptors

0

NA ^cm-3 Concentration of unionized acceptors N_b,Y

Number of nodes beneath the bus bar in direction parallel to the fingers in a distributed circuit model of a solar cell

N_bf,X

Number of nodes between two adjacent fingers in direction perpendicular to them in a distributed circuit model of a solar cell

NC cm^-3 Effective density of states in the conduction band

N_D cm^-3 Total concentration of donors

+

ND ^cm-3 Concentration of ionized donors

0

ND ^cm-3 Concentration of unionized donors

Nf,X

Number of nodes beneath one grid finger in direction perpendicular to it in a distributed circuit model of a solar cell

N_f,Y

Number of nodes in the area of the grid fingers in direction parallel to them in a distributed circuit model of a solar cell

N_front cm^-3 Front surface doping concentration of an emitter

profile

ni cm^-3 Intrinsic carrier concentration at thermal equilibrium n_n cm^-3 Electron concentration at the edge of the space charge

region in the n-doped material

n_p cm^-3 Electron concentration at the edge of the space charge region in the p-doped material

nS cm^-3 Concentration of electrons at the surface

Variable (Usual)

Dimension Meaning

Nt cm^-3 Defect concentration

NV cm^-3 Effective density of states in the valence band

p cm^-3 Hole density in the valence band

p0 cm^-3 Hole concentration in the valance band at thermal equilibrium

p1 cm^-3 SRH density for holes

P_in W/cm² Power density of an external illumination

corr suns

PLIVoc_,0.2

PL-image obtained under V_oc conditions and 0.2 suns equivalent illumination intensity, which is corrected for lifetime effects

corr onesun

PLIVext_,

PL-image obtained applying an external voltage V_ext and one sun equivalent illumination intensity, which is corrected for lifetime effects

PLIJsc,0.2suns

PL-image taken at J_sc-conditions and 0.2 suns equivalent illumination intensity

PLIJsc,onesun

PL-image taken at Jsc-conditions and one sun equivalent illumination intensity

PLIVoc,0.2suns

PL-image taken at Voc-conditions and 0.2 suns equivalent illumination intensity

PLIVext,onesun

PL-image taken at externally applied voltage V_ext- and one sun equivalent illumination intensity

Ploss W Power loss in a solar cell due to (emitter) resistances p_n cm^-3 Hole concentration at the edge of the transition region

in the n-doped material

p_p cm^-3 Hole concentration at the edge of the transition region in the p-doped material

p_s cm^-3 Concentration of holes at the surface

q Elementary charge, 1.602 176 462(63)×10^-19 C [117]

R s^-1 cm^-3 Total recombination rate

R₀ s^-1 cm^-3 Recombination rate at thermal equilibrium R_ARC Reflectance of the anti reflectance coating

Im Dokument Analyses of silicon solar cells and their measurement methods by distributed circuit simulations and by experiment (Seite 196-0)