Rahul Dewan - Jacobs University

6. SIMPLER AND FASTER METHOD FOR PERIODIC TEXTURES - USING RIGOROUS
COUPLED WAVE ANALYSIS
mA/cm 2
(a)
(b)
(c)
Figure 6.4: Short circuit current for a 1-µm-thick microcrystalline silicon solar cell as a
function of the grating period and height illuminated under (a) blue light (wavelength
300 – 500 nm), (b) red and infrared light (wavelength 700 – 1100 nm), and (c) entire
sun spectrum (wavelength 300 – 1100 nm). The set of figures show the behavior of
solar cells with integrated line grating.
current compared with that of the flat case is observed. When illuminated by an AM 1.5
sun spectrum [Figs. 6.4(c) and 6.5(c)], the maximum short circuit current is observed
for grating periods of approximately 500 - 700 nm. Compared with the short circuit
current of a solar cell on a smooth substrate, the short circuit current is increased by
around 60% from 13 to 20 and 21 mA/cm 2 for the line grating and triangular grating,
respectively. The behavior of the short circuit current in Figs. 6.4 and 6.5 as a function
of the grating period can be explained as follows: For grating periods much smaller
than the incident wavelength, only a slight enhancement of the short circuit current
is observed for the blue part of the optical spectrum. The enhancement of the short
circuit current is caused by an improved incoupling of shorter-wavelength light [Figs.
6.4(a) and 6.5(a)]. Compared with a solar cell on a smooth substrate, an enhancement
82