Abstract:The effect of light soaking (LS) is studied in hydrogenated amorphous silicon (a-Si:H) containing different amounts of nanocrystals, prepared by varying the deposition conditions in a plasma enhanced chemical vapor deposition (PECVD) system. We find that the presence of nanocrystals (nc-Si) stabilizes the a-Si:H against LS. The long range potential fluctuations (LRPF) are measured and we find that they become smaller as the fraction of nanocrystals (χ) in the films increases. Raman spectra show a peak at 490 c… Show more
“…They are deposited under 300 Pa, 450 Pa, 750 Pa, and 1050 Pa, respectively. Each spectrum (open circles) under certain pressure can be deconvoluted into three Gaussian peaks: (1) a broad Gaussian distribution around 480 cm −1 , which is attributed to the transverse optical (TO 1 ) mode of amorphous silicon; (2) a peak near 520 cm −1 , which belongs to the asymmetric TO 2 vibrational mode of crystalline silicon [ 13 , 14 ]; and (3) the peak around 506 cm −1 which is attributed to the intermediate range order [ 1 , 15 ]. The crystallinity ( X c ) in nc-Si:H can be calculated by [ 16 , 17 ]: Fig.…”
Section: Resultsmentioning
confidence: 99%
“…An important landmark in the progress of thin film silicon technology is the development of high-quality hydrogenated nanocrystalline silicon (nc-Si:H). Compared with hydrogenated amorphous silicon (a-Si:H), nc-Si:H has much higher mobility, much better response at wavelengths greater than 800 nm, and is much less susceptible to the Staebler-Wronski degradation [ 1 , 2 ]. nc-Si:H thin film can be deposited using plasma-enhanced chemical vapor deposition (PECVD), which makes it compatible with well-developed integrated circuit industry.…”
Hydrogenated nanocrystalline silicon (nc-Si:H) thin film has received a great deal of attention as a promising material for flat panel display transistors, solar cells, etc. However, the multiphase structure of nc-Si:H leads to many defects. One of the major challenges is how to reduce the defects conveniently. In this work, we developed a simple and effective method to deposit low-defect-density nc-Si:H thin film. This method is simply by tuning the deposition pressure in a high-pressure range in plasma-enhanced chemical vapor deposition (PECVD) process. Microstructures of the nc-Si:H were characterized by Raman, AFM, and SEM. Furthermore, we focused on the defect density which was the key characteristic for photovoltaic materials and achieved the defect density of 3.766 × 1016 cm−3. This defect density is lower than that of previous studies on the fabrication of low-defect-density nc-Si:H by other complex methods in PECVD process. The minority carrier lifetime of nc-Si:H is thus greatly improved. Moreover, we demonstrated the mechanism about the effect of deposition pressure on the ion bombardment and proved that the defect density is the key characteristic for nc-Si:H photovoltaic material.Electronic supplementary materialThe online version of this article (10.1186/s11671-018-2641-z) contains supplementary material, which is available to authorized users.
“…They are deposited under 300 Pa, 450 Pa, 750 Pa, and 1050 Pa, respectively. Each spectrum (open circles) under certain pressure can be deconvoluted into three Gaussian peaks: (1) a broad Gaussian distribution around 480 cm −1 , which is attributed to the transverse optical (TO 1 ) mode of amorphous silicon; (2) a peak near 520 cm −1 , which belongs to the asymmetric TO 2 vibrational mode of crystalline silicon [ 13 , 14 ]; and (3) the peak around 506 cm −1 which is attributed to the intermediate range order [ 1 , 15 ]. The crystallinity ( X c ) in nc-Si:H can be calculated by [ 16 , 17 ]: Fig.…”
Section: Resultsmentioning
confidence: 99%
“…An important landmark in the progress of thin film silicon technology is the development of high-quality hydrogenated nanocrystalline silicon (nc-Si:H). Compared with hydrogenated amorphous silicon (a-Si:H), nc-Si:H has much higher mobility, much better response at wavelengths greater than 800 nm, and is much less susceptible to the Staebler-Wronski degradation [ 1 , 2 ]. nc-Si:H thin film can be deposited using plasma-enhanced chemical vapor deposition (PECVD), which makes it compatible with well-developed integrated circuit industry.…”
Hydrogenated nanocrystalline silicon (nc-Si:H) thin film has received a great deal of attention as a promising material for flat panel display transistors, solar cells, etc. However, the multiphase structure of nc-Si:H leads to many defects. One of the major challenges is how to reduce the defects conveniently. In this work, we developed a simple and effective method to deposit low-defect-density nc-Si:H thin film. This method is simply by tuning the deposition pressure in a high-pressure range in plasma-enhanced chemical vapor deposition (PECVD) process. Microstructures of the nc-Si:H were characterized by Raman, AFM, and SEM. Furthermore, we focused on the defect density which was the key characteristic for photovoltaic materials and achieved the defect density of 3.766 × 1016 cm−3. This defect density is lower than that of previous studies on the fabrication of low-defect-density nc-Si:H by other complex methods in PECVD process. The minority carrier lifetime of nc-Si:H is thus greatly improved. Moreover, we demonstrated the mechanism about the effect of deposition pressure on the ion bombardment and proved that the defect density is the key characteristic for nc-Si:H photovoltaic material.Electronic supplementary materialThe online version of this article (10.1186/s11671-018-2641-z) contains supplementary material, which is available to authorized users.
Thin films of mixed amorphous/ microcrystalline-phases have been researched during the last decade, for manufacturing silicon solar cells. In this work the Plasma Enhanced Chemical Vapor Deposition PECVD process parameters; namely dilution ratios and substrate temperature, were controlled to build i-layer at low dilution ratios with moderate substrate temperatures. In this work an intrinsic layer was deposited on Indium Tin Oxide ITO glass by PECVD technique, with different dilution ratios of silane in hydrogen to study the transition from amorphous to microcrystalline phase. The Si:H thin film was evaluated by field emission scanning electron microscopy, x-ray diffraction and atomic force microscopy. The structural transition between a-Si:H to μc-Si:H achieved at dilution ratio 13.3 and substrate temperature 250°C with surface roughness 22.5 nm.
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