Low Reverse Saturation Current Density of Amorphous Silicon Solar Cell Due to Reduced Thickness of Active Layer

Abstract

-One of the most important characteristic curves of a solar cell is its current density-voltage (J-V) curve under AM1.5G insolation. Solar cell can be considered as a semiconductor diode, so a diode equivalent model was used to estimate its parameters from the J-V curve by numerical simulation. Active layer plays an important role in operation of a solar cell. We investigated the effect thicknesses and defect densities (N d ) of the active layer on the J-V curve. When the active layer thickness was varied (for N d = 8×10 17 cm -3 ) from 800 nm to 100 nm, the reverse saturation current density (J o ) changed from 3.56×10 -5 A/cm 2 to 9.62×10 -11 A/cm 2 and its ideality factor (n) changed from 5.28 to 2.02. For a reduced defect density (N d = 4×10 15 cm -3 ), the n remained within 1.45≤n≤1.92 for the same thickness range. A small increase in shunt resistance and almost no change in series resistance were observed in these cells. The low reverse saturation current density (J o = 9.62×10 -11 A/cm 2 ) and diode ideality factor (n = 2.02 or 1.45) were observed for amorphous silicon based solar cell with 100 nm thick active layer.

Improving the efficiency of rear emitter silicon solar cell using an optimized n-type silicon oxide front surface field layer

“…This change in device characteristics indicates a change in the recombination of carriers as well as in the series resistance (R s ) of the cell. An increased carrier recombination is thought to be related to an increased reverse saturation current density (J 0 ) 40 . If photo-generated carriers are not collected efficiently, they can influence electric field distribution within the device, because of which the effective diode ideality factor (DIF) of the device can also increase.…”

“…If photo-generated carriers are not collected efficiently, they can influence electric field distribution within the device, because of which the effective diode ideality factor (DIF) of the device can also increase. Therefore, DIF can also be called as a shielding parameter related to the electric field inside the device 43 ; information on such parameters can be obtained by an analysis of the single diode-equivalent-circuit of the solar cells 39 , 40 . The calculated parameters are listed in Table 3 .…”

“…Furthermore, we simulated device characteristics, when the characteristics were similar to the experimentally measured one; we use those conditions for estimating the band diagrams. The diode equivalent parameters of the cells were estimated by using single diode model, and by numerical simulation 39 , 40 .…”

HF etched glass substrates for improved thin-film solar cells

“…It is evident that the J sc and FF were improved and resulted in the improvement of the overall efficiency of the analogous periodic-texture-etched glass. For an increased FF upon rougher glass surface with HF 35% etching, which is related to the increase in the parallel resistance and the decrease in the series resistance [ 20 , 21 ], as shown in Table 1 . During the deposition, the thickness of the amorphous silicon layers depends on the multi-scale surface (TCO film/textured glass) [22] .…”

Fabrication of honeycomb textured glass substrate and nanotexturing of zinc oxide front electrode for its application in high efficiency thin film amorphous silicon solar cell

“…The J − V characteristic curves and the EQE spectra are shown in Figs. 34,35 But increase in J sc is an indication of better light trapping. The solar cell parameters were extracted from Fig.…”