Surface and bulk passivation of multicrystalline silicon solar cells by ...
Surface and bulk passivation of multicrystalline silicon solar cells by ...
Surface and bulk passivation of multicrystalline silicon solar cells by ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
29<br />
ratio, <strong>and</strong> the amount <strong>of</strong> unbound H. As a result, a wide range <strong>of</strong> properties can be<br />
obtained <strong>by</strong> managing these structural <strong>and</strong> chemical properties <strong>by</strong> manipulating the<br />
deposition parameters [42].<br />
Optical properties, such as absorption, reflection <strong>and</strong> refractive index <strong>of</strong> the SIN<br />
AR coating, depend significantly on the concentration <strong>and</strong> chemical distribution <strong>of</strong><br />
hydrogen, <strong>silicon</strong> <strong>and</strong> nitrogen in the film, i.e., on the deposition conditions, which are<br />
controlled <strong>by</strong> the N/Si ratio (x) in the films. For small x, the hydrogen-bonding<br />
configuration consists <strong>of</strong> isolated Si—H bonds, with no adjacent Si—N bonds. As x<br />
increases, multi-N-bonded Si—H bonds dominate the structure. For x>1, N—H bonds start<br />
to form <strong>and</strong> increase with x. Thus, a means <strong>of</strong> controlling the material properties <strong>of</strong> the<br />
SiN X films consists <strong>of</strong> simply adjusting the x value <strong>by</strong> changing the nitrogen content.<br />
Figure 2.6 The refractive index as a function <strong>of</strong> N/Si ratio for SiΝ :Η films [52]. A line is<br />
drawn through the data for visual guidance only.