R
recombination rate, m
−3 s
−1
R
reflectivity, −
S r
surface recombination velocity, ms
−1
T
temperature, K
T
transmittance, −
U
heat exchange coefficient, WK
−1
V
electric potential, V
v, υ
velocity, ms
−1
W
work, J
z
height (function), m
Greek letters
α
absorption coefficient, −
α
albedo, −
γ
angle of incidence, −
∈
electric permittivity, −
∈
emissivity, −
ζ
magnetic field, Am
−1
η
efficiency, −
θ
polar angle, generic angle, −
κ
refractive index (imaginary part), −
λ
wavelength, m
μ
mobility, m
2
V
−1 s
−1