Basic solar cell design includes P-N junction with thin N layer being at top and bulk P layer at bottom. It is designed without the ARC coating. But since bare silicon is oxidised due to reaction of oxygen so top and bottom side of solar cell is thin silica oxide layer.
Dimensions of solar cell-
Overall dimension of cell=14 x 10 x 6 um (considered for simulation)
N – type layer at top of cell diffused doping surface concentration = 10^19 /cm3 and reference concentration = 10^10/cm3, With thickness of 1 um and junction width of 0.4 um.
Remaining material is p-type doped with density 10^16/cm3.
At upper and lower surfaces 1 um thick silicon oxide layer.
At top emitter side the silver current collector wire of 2 um breadth and 0.5um thickness.
At bottom base side aluminium current collector of 1 um thickness.
The picture of lumerical simulation model is given below-
To do the simulation in device first of all we need generation curve(wavelength range 0.3 – 1.1 um) which is obtained from the FDTD. Generation curve gives the variotion of electon hole pair generation with the solar cell depth.
After that we imported the generation rate data in the device applied biasing across the solar cell to get the following I-V curve.
This curve shows the variation of current density of solar cell with respect to the voltage.
The short circuit current is maximum current of solar cell obtained at zero voltage, and open circuit voltage is maximum voltage obtained at open circuit i.e. zero current. It is showing that the current is nearly constant up to certain voltage after that it falls very fast.
The above curve shows the power density variation with respect to voltage. We can get the maximum value of power from the above curve so that we can find the efficiency.
Efficiency η % =( Pmax / solar irradiance at 1.5 AM) * 100.
Results.=
Voc = 562.222 mV
Jsc = 12.37 mA/cm^2
Pmax = 5.76976 mW/cm^2
η % = 5.76976%
