Surface and bulk passivation of multicrystalline silicon solar cells by ...

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and Qf at SiΝ -Si interface are approximately one order in magnitude higher than that for
the Si-SiO 2 interface.
Similarly, the deposition of SiNX layers on silicon substrates lead to the formation
of a space charge region at the interface characterized by a fixed positive charge density
(Qf) of the order of 1012cm-2. In p-type Si, a depletion/inversion layer is formed, while in
n-type Si, the positively charged insulator attracts majority carriers and repels minority
carriers. Hence, an accumulation layer is formed.
3.2.1 Program for SRV Calculations
Based on the extended SRH formalism, a program is written to calculate the SRV at
dielectric film-Si interface. A brief description of the algorithm and methodology of this
program is as follows:
There are only two differences in the programs between the n-Si and p-Si:
1. The p-type uses the Na input parameter while the n-type uses the Nd input
parameter;
2. The p and n types use slightly different equations to determine the bandbending
(phi_s), recombination rate (Us), surface recombination velocity (Se) values.
It is the same exact numerical method for both types.
The method:
1. The programs asks for input parameters (see note below);
2. The programs have an outer and inner loop: the outer loop is controlled by the
m value while the inner loop is controlled by the n value; together, these m, n parameters
control the energy at which the phis. Us and Se will be calculated; the formula is delta n