Numerical simulation of functional characteristics of solar elements InGaAsN/Si

For the first time, numerical simulation and optimization of the current-voltage characteristics of a fundamentally new single-junction solar cell based on the InxGa1–xAs1–yNy/Si heterostructure were carried out. The integration of multicomponent layers A3B5 and dilute nitrides A3B5N with silicon substrates is currently a technologically complex process. Despite the complexity of this integration, there are certain prerequisites that may make it possible to obtain InxGa1–xAs1–yNy layers with a relatively low defect density. The InxGa1–xAs1–yNy solid solution is quite promising for use in optoelectronics, but at the same time it is poorly studied. Numerical modeling was carried out using the AFORS HET v2.5 software product. When numerically calculating the parameters of the solar cell In0.02Ga0.98As1–yNy/Si, we obtained the following data: the nitrogen concentration y varied in the range from 0 to 5 %; the thickness of the In0.02Ga0.98As1–yNy layer varied within 0,3–0,8 μm; the degree of doping of the base and the emitter of the SC varied in the range 1016–8·1019 cm–3. The dependences of the current-voltage and spectral characteristics on the thickness and composition of the emitter, as well as the degree of doping of the layers were investigated. It is shown that solar cells consisting of the In0.02Ga0.98As0.98N0.02/Si heterojunction can achieve an efficiency of 22.2 % under illumination AM1.5. Modeling the effect of nitrogen concentration on the efficiency of solar cells showed that a change in nitrogen concentration from 0 to 5 % in the In0.02Ga0.98As1–yNy layer leads to a decrease in the efficiency of 21.9 % to 21.82 %, respectively. This fact is primarily due to a decrease in the value of the energy gap of the emitter and, as a consequence, to a decrease in the value of the open circuit voltage of the solar cell. It was found that an increase in the impurity concentration in the In0.02Ga0.98As0.98N0.02 emitter in the range 1016–8·1019 cm–3 leads to an increase in the solar cell efficiency from 17.11 % to 21.89 %, respectively. With an increase in the impurity concentration in the p-Si base in the range from 1016–5·1017 cm–3, a steady increase in efficiency is observed up to 22.2 %, and then a monotonic decrease to 10.87 % at an impurity concentration of 5·1017 cm–3. With a decrease in the emitter thickness, the quantum efficiency of a solar cell increases due to a decrease in the number of photogenerated charge carriers. As a result of numerical simulation in the AFORS HET v2.5 software product, it was determined that the open-circuit voltage of solar cells based on the n-In0.02Ga0.98As0.98N0.02/p-Si heterostructure is 716.8 mV, at a short-circuit current density of 36.52 mA/cm2, fill factor equal to 84.81 % and efficiency equal to 22.2 %.