Optimization of effective doping concentration of emitter for ideal c-Si solar cell device with PC1D simulation

Increasing silicon solar cell efficiency plays a vital role in improving the dominant market share of photo-voltaic systems in the renewable energy sector. The performance of the solar cells can be evaluated by making a profound analysis on various effective parameters, such as the sheet resistance, doping concentration, thickness of the solar cell, arbitrary dopant profile, etc., using software simulation tools, such as PC1D. In this paper, we present the observations obtained from the evaluation carried out on the impact of sheet resistance on the solar cell’s parameters using PC1D software. After which, the EDNA2 simulation tool was used to analyse the emitter saturation current density for the chosen arbitrary dopant profile. Results indicated that the diffusion profile with low surface concentration and shallow junction depth can improve the blue response at the frontal side of the solar cell. The emitter saturation current density decreases from 66.52 to 36.82 fA/cm2 for the subsequent increase in sheet resistance. The blue response also increased from 89.6% to 97.5% with rise in sheet resistance. In addition, the short circuit density and open circuit voltage was also observed to be improved by 0.6 mA/cm2 and 3 mV for the sheet resistance value of 130 Ω/sq, which resulted in achieving the highest efficiency of 20.6%

X-ray photoelectron spectroscopy and X-ray diffraction studies on tin sulfide films grown by sulfurization process

Tin sulfide (SnS) thin films were grown by single zone sulfurization process using sputtered tin layers. Metallic tin (Sn) layers were grown on molybdenum (Mo) coated soda-lime glass substrates by DC magnetron sputtering. The sputtered Sn layers along with sulfur flakes were kept in a graphite box and sulfurized using a closed single zone quartz tube furnace at different temperatures that vary in the range of 200–350 °C for a fixed sulfurization time of 2 h. The X-ray photoelectron spectroscopy studies on these layers revealed approximately stoichiometric ratio of Sn/S at a sulfurization temperature of 350 °C. The X-ray diffraction studies revealed the presence of secondary phases such as SnS 2 and Sn2S3 at lower sulfurization temperatures that got suppressed with the rise of temperature. All the layers showed the (111) plane as preferential orientation with orthorhombic structure and its intensity increased with the increase of sulfurization temperature. The evaluated crystallite size of the layers was found to increase with the increase of sulfurization temperature

Development of sulphurized SnS thin film solar cells

Thin films of tin sulphide (SnS) have been grown by sulphurization of sputtered tin precursor layers in a closed chamber. The effect of sulphurization temperature (Ts) that varied in the range of 150–450 °C for a fixed sulphurization time of 120 min on SnS film was studied through various characterization techniques. X-ray photoelectron spectroscopy analysis demonstrated the transformation of metallic tin layers into SnS single phase for Ts between 300 °C and 350 °C. The X-ray diffraction measurements indicated that all the grown films had the (111) crystal plane as the preferred orientation and exhibited orthorhombic crystal structure. Raman analysis showed modes at 95 cm−1, 189 cm−1 and 218 cm−1 are related to the Ag mode of SnS. AFM images revealed a granular change in the grain growth with the increase of Ts. The optical energy band gap values were estimated using the transmittance spectra and found to be varied from 1.2 eV to 1.6 eV with Ts. The Hall effect measurements showed that all the films were p-type conducting nature and the layers grown at 350 °C showed a low electrical resistivity of 64 Ω-cm, a net carrier concentration of 2 × 1016 cm−3 and mobility of 41 cm2 V−1 s−1. With the use of sprayed Zn0.76Mg0.24O as a buffer layer and the sputtered ZnO:Al as window layer, the SnS based thin film solar cell was developed that showed a conversion efficiency of 2.02%

Physical properties of ZnxCd1-xS nanocrystalline layers synthesized by solution growth method

In recent years, zinc cadmium sulphide (ZnxCd1-xS) alloy compounds have paid much attention in the fields of opto-electronics, particularly in photovoltaic devices because of its tunable energy gap and the lattice parameters. The energy band gap of ZnxCd1-xS is controlled by the change of Zn-composition in order to suit the material properties with that of absorber material in solar cells. In this paper, we report on the effect of Zn-composition on physical properties of ZnxCd1-xS thin films deposited on corning glass substrates by solution growth method. The layers were prepared for different ‘x’ values that vary in the range, 0 – 1.0 at. %. The as-grown layers were characterized using EDAX, XRD, SEM, and UV-Vis-NIR spectrophotometers. All the layers showed a strong (002) plane as the preferred orientation that exhibited the hexagonal crystal structure. The composition of the layers agrees approximately with that of the elements in the solution. The films showed an average optical transmittance of 72 % at a zinc composition of 0.75 with a band gap of 3.88 eV

Influence of the Al-Doped ZnO Sputter-Deposition Temperature on Cu(In,Ga)Se₂ Solar Cell Performance

Heterojunction Cu(In,Ga)Se2 (CIGS) solar cells comprise a substrate/Mo/CIGS/CdS/i-ZnO/ZnO:Al. Here, Al-doped zinc oxide (AZO) films were deposited by magnetron sputtering, and the substrate temperature was optimized for CIGS solar cells with two types of CIGS light absorbers with different material properties fabricated by three-stage co-evaporation and two-step metallization followed by sulfurization after selenization (SAS). The microstructure and optoelectronic properties of the AZO thin films fabricated at different substrate temperatures (150–550 °C) were analyzed along with their effects on the CIGS solar cell performance. X-ray diffraction results confirmed that all the deposited AZO films have a hexagonal wurtzite crystal structure regardless of substrate temperature. The optical and electrical properties of the AZO films improved significantly with increasing substrate temperature. Photovoltaic performances of the two types of CIGS solar cells were influenced by changes in the AZO substrate temperature. For the three-stage co-evaporated CIGS cell, as the sputter-deposition temperature of the AZO layer was raised from 150 °C to 550 °C, the efficiencies of CIGS devices decreased monotonically, which suggests the optimum AZO deposition temperature is 150 °C. In contrast, the cell efficiency of CIGS devices fabricated using the two-step SAS-processed CIGS absorbers improved with increasing the AZO deposition temperature from 150 to 350 °C. However, the rise in AZO deposition temperature to 550 °C decreased the cell efficiency, indicating that the optimum AZO deposition temperature was 350 °C. The findings of this study provide insights for the efficient fabrication of CIGS solar cells considering the correlation between CIGS absorber characteristics and AZO layer deposition temperature

Influence of Different Substrates on the Properties of Sulfurized SnS Films

SnS films were grown on a variety of substrates, such as Al, Si, Mo, Ni, ITO, and glass, maintaining a constant sulfurization temperature of 350 C and time of 150 min using elemental sulfur via a two-stage process. The influence of the various types of substrates on the growth and physical properties was examined by Xray diffraction (XRD), Raman spectroscopy, scanning electron microscopy, and electrical measurements. The XRD profiles indicated that the as-prepared films were in a polycrystalline nature with different planes as the preferred orientations and exhibited an orthorhombic crystal structure. The Raman spectra revealed bands at 95 cm−1, 189 cm−1 and 219 cm−1; and 163 cm−1, which were assigned to the Ag and B2g phonon modes of SnS, respectively. The surface morphology revealed complete coverage of the grains with good compactness. Electrical studies yielded interesting results in that the SnS films grown on glass substrates showed a higher electrical resistivity of 45 -cm compared to the other substrates but all the films exhibited p-type conductivity

Crystalline behaviour of SnS layers produced by sulfurization of Sn films using H2S

Tin sulfide (SnS) is receiving increasing interest for its potential application as an absorber layer in thin film solar cells. In this work, a novel method for the formation of SnS layers on soda-lime glass substrates was investigated. The layers were formed by first sputtering tin onto glass followed by annealing in a 5% H2S and Ar gas environment over the temperature range of 300-450°C for 2 hours. The structural properties of the layers synthesized, including the crystal structure, phases present, crystallite size, strain and dislocation density are reported

CBD ZnIn2Se4 AS buffer layer for CuInGaSe2 thin film solar cells

Tin sulfide (SnS) is receiving increasing interest for its potential application as an absorber layer in thin film solar cells. In this work, a novel method for the formation of SnS layers on soda-lime glass substrates was investigated. The layers were formed by first sputtering tin onto glass followed by annealing in a 5% H2S and Ar gas environment over the temperature range of 300-450°C for 2 hours. The structural properties of the layers synthesized, including the crystal structure, phases present, crystallite size, strain and dislocation density are reported

Synthesis and Characterization of Cu2ZnSnSe4 by Non-Vacuum Method for Photovoltaic Applications

Wet ball milling was used for the synthesis of Cu2ZnSnSe4 (CZTSe) nanoparticles with a kesterite structure. The prepared nanoparticles were used for ink formulation. Surfactants and binders were added to improve the ink stability, prevent agglomeration, and enhance ink adhesion. The films deposited via spin coating were annealed at different temperatures using a rapid thermal processing system in the presence of selenium powder in an inert environment. Analytical techniques, such as X-ray diffraction, Raman spectroscopy, and Fourier-transform infrared spectroscopy, were used to confirm the formation of CZTSe nanoparticles with a single-phase, crystalline kesterite structure. Field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to study the surface morphology and chemical composition of the thin films before and after annealing, with and without the sodium solution. The optoelectrical properties were investigated using ultraviolet-visible spectroscopy and Hall measurements. All the prepared CZTSe thin films exhibited a p-type nature with an optical bandgap in the range of 0.82–1.02 eV. The open-circuit voltage and fill factor of the CZTSe-based devices increased from 266 to 335 mV and from 37.79% to 44.19%, respectively, indicating a decrease in the number of recombination centers after Na incorporation

Effect of Sulfurization Time on the Physical Properties of Tin (II) Monosulfide Thin Films

Tin (II) monosulfide (SnS) films were prepared via sulfurization using sputtered Sn precursors of the tin metal layers in the presence of elemental sulfur vapor as a function of sulfurization time (ts) in the range of 30–180 min while keeping other parameters constant. The properties of these sulfurized layers were examined through suitable characterization techniques. The diffraction patterns exhibited various planes with the orientations (110), (120), (021), (101), (111), (211), (131), (210), (141), (002), (112), (122), and (042) corresponding to orthorhombic SnS at ts ≤ 90 min. However, for ts ≥ 120 min, the diffraction patterns showed a single (111) plane and enhanced the intensity of the peak with the increase of ts up to 150 min; with further increase of time, the peak intensity was found to decrease. The Raman spectra of films sulfurized at various ts showed modes at 95, 162, 189, 219, and 284 cm−1 for times were lower than 120 min and 95, 189, and 219 cm−1 for ts ≥ 120 min, related to SnS. In the transmittance spectra of the sulfurized films, it is clear that the film grown at ts = 30 min had higher transmittance, and with the increase of ts to 120 min, transmittance was decreased. For further extension of ts to 150 min, a sharp falling of the absorption edge was observed