Hydrogenated microcrystalline silicon (μc-Si:H) thin films were prepared by high- pressure radio-frequency (13.56 MHz) plasma enhanced chemical vapor deposition (rf-PECVD) with a screened plasma. The deposition rate ...Hydrogenated microcrystalline silicon (μc-Si:H) thin films were prepared by high- pressure radio-frequency (13.56 MHz) plasma enhanced chemical vapor deposition (rf-PECVD) with a screened plasma. The deposition rate and crystallinity varying with the deposition pressure, rf power, hydrogen dilution ratio and electrodes distance were systematically studied. By optimizing the deposition parameters the device quality μc-Si:H films have been achieved with a high deposition rate of 7.8 /s at a high pressure. The Voc of 560 mV and the FF of 0.70 have been achieved for a single-junction μc-Si:H p-i-n solar cell at a deposition rate of 7.8 /s.展开更多
Raman spectra and scanning electron microscope （SEM） techniques were used to determine the structural properties of microcrb＇stalline silicon （μc-Si：H） films deposited on different substrates with the very high...Raman spectra and scanning electron microscope （SEM） techniques were used to determine the structural properties of microcrb＇stalline silicon （μc-Si：H） films deposited on different substrates with the very high frequency plasma-enhanced chemical vapor deposition （VHF-PECVD） technique. Using the Raman spectra, the values of crystalline volume fraction Xc and average grain size d are 86%, 12.3nm; 65%, 5.45nm; and 38%, 4.05nm, for single crystalline silicon wafer, coming 7059 glass, and general optical glass substrates, respectively. The SEM images further demonstrate the substrate effect on the film surface roughness. For the single crystalline silicon wafer and Coming 7059 glass, the surfaces of the μc-Si：H films are fairly smooth because of the homogenous growth or h＇ttle lattice mismatch. But for general optical glass, the surface of the μ-Si： H film is very rough, thus the growing surface roughness affects the crystallization process and determines the average grain size of the deposited material. Moreover, with the measurements of thickness, photo and dark conductivity, photosensitivity and activation energy, the substrate effect on the deposition rate, optical and electrical properties of the μc-Si：H thin films have also been investigated. On the basis of the above results, it can be concluded that the substrates affect the initial growing layers acting as a seed for the formation of a crystalline-like material and then the deposition rates, optical and electrical properties are also strongly influenced, hence, deposition parameter optimization is the key method that can be used to obtain a good initial growing layer, to realize the deposition of μc-Si：H films with device-grade quality on cheap substrates such as general glass.展开更多
Hydrogenated microcrystalline silicon （μc-Si：H） films are fabricated by very high frequency plasma enhanced chemical vapour deposition （VHF-PECVD） at a silane concentration of 7% and a varying total gas flow ra...Hydrogenated microcrystalline silicon （μc-Si：H） films are fabricated by very high frequency plasma enhanced chemical vapour deposition （VHF-PECVD） at a silane concentration of 7% and a varying total gas flow rate （H2＋SiH4）. Relations between the total gas flow rate and the electrical and structural properties as well as deposition rate of the films are studied. The results indicate that with the total gas flow rate increasing the photosensitivity and deposition rate increase, but the crystalline volume fraction （Xc） and dark conductivity decrease. And the intensity of （220） peak first increases then decreases with the increase of the total gas flow rate. The cause for the changes in the structure and deposition rate of the films with the total gas flow rate is investigated using optical emission spectroscopy （OES）.展开更多
采用RF PECVD方法,在P a SiC:H薄膜沉积技术基础上,通过逐步减小碳、硼的掺杂浓度,增大氢稀释率,使材料从非晶态向微晶态转变,在获得本征微晶材料之后,再逐步增大硼掺杂浓度,得到P型微晶硅薄膜材料(暗电导率为5.22×10-3S/cm,光学...采用RF PECVD方法,在P a SiC:H薄膜沉积技术基础上,通过逐步减小碳、硼的掺杂浓度,增大氢稀释率,使材料从非晶态向微晶态转变,在获得本征微晶材料之后,再逐步增大硼掺杂浓度,得到P型微晶硅薄膜材料(暗电导率为5.22×10-3S/cm,光学带隙大于2.0eV)。在这个过程中可以明显观察到碳、硼抑制材料晶化的作用。展开更多
采用射频等离子体增强化学气相沉积（RF-PECVD）法在低温、低功率的条件下制备了一系列本征硅薄膜,研究了硅烷浓度（CS）对薄膜微结构、光电特性及表面钝化性能的影响.将本征硅薄膜作为钝化层应用到氢化纳米晶硅/晶硅（nc-Si：H/c-Si）...采用射频等离子体增强化学气相沉积（RF-PECVD）法在低温、低功率的条件下制备了一系列本征硅薄膜,研究了硅烷浓度（CS）对薄膜微结构、光电特性及表面钝化性能的影响.将本征硅薄膜作为钝化层应用到氢化纳米晶硅/晶硅（nc-Si：H/c-Si）硅异质结（SHJ）太阳电池中,研究了硅烷浓度和薄膜厚度对电池性能的影响.实验发现：随着硅烷浓度的降低,本征硅薄膜的晶化率、氢含量、结构因子、光学带隙和光敏性等都在过渡区急剧变化;本征硅薄膜的钝化性能由薄膜的氢含量及氢的成键方式决定.靠近过渡区的薄膜具有较好的致密性和光敏性,氢含量最高,带隙态密度低,且主要以Si H形式成键,对硅片表现出优异的钝化性能,使电池的开路电压大幅提高.但是,当薄膜的厚度过小时,会严重影响其钝化质量.本实验中,沉积本征硅薄膜的最优硅烷浓度为6%（摩尔分数）,且当薄膜厚度为~8 nm时,所制备电池的性能最好.实验最终获得了开路电压为672 m V,短路电流密度为35.1 m A·cm-2,填充因子为0.73,效率为17.3%的nc-Si：H/c-Si SHJ太阳电池.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 50662003)the State Development Program for Basic Research of China (Grant No. G2000028208)
文摘Hydrogenated microcrystalline silicon (μc-Si:H) thin films were prepared by high- pressure radio-frequency (13.56 MHz) plasma enhanced chemical vapor deposition (rf-PECVD) with a screened plasma. The deposition rate and crystallinity varying with the deposition pressure, rf power, hydrogen dilution ratio and electrodes distance were systematically studied. By optimizing the deposition parameters the device quality μc-Si:H films have been achieved with a high deposition rate of 7.8 /s at a high pressure. The Voc of 560 mV and the FF of 0.70 have been achieved for a single-junction μc-Si:H p-i-n solar cell at a deposition rate of 7.8 /s.
基金This work was supported by the National Key Basic Research and Development Programme of China （No. G2000028202 and G2000028203） Guangdong Provincial Natural Science Foundation of China （No. 05300378） Programme on Natural Science of Jinan University （No. 51204056）.
文摘Raman spectra and scanning electron microscope （SEM） techniques were used to determine the structural properties of microcrb＇stalline silicon （μc-Si：H） films deposited on different substrates with the very high frequency plasma-enhanced chemical vapor deposition （VHF-PECVD） technique. Using the Raman spectra, the values of crystalline volume fraction Xc and average grain size d are 86%, 12.3nm; 65%, 5.45nm; and 38%, 4.05nm, for single crystalline silicon wafer, coming 7059 glass, and general optical glass substrates, respectively. The SEM images further demonstrate the substrate effect on the film surface roughness. For the single crystalline silicon wafer and Coming 7059 glass, the surfaces of the μc-Si：H films are fairly smooth because of the homogenous growth or h＇ttle lattice mismatch. But for general optical glass, the surface of the μ-Si： H film is very rough, thus the growing surface roughness affects the crystallization process and determines the average grain size of the deposited material. Moreover, with the measurements of thickness, photo and dark conductivity, photosensitivity and activation energy, the substrate effect on the deposition rate, optical and electrical properties of the μc-Si：H thin films have also been investigated. On the basis of the above results, it can be concluded that the substrates affect the initial growing layers acting as a seed for the formation of a crystalline-like material and then the deposition rates, optical and electrical properties are also strongly influenced, hence, deposition parameter optimization is the key method that can be used to obtain a good initial growing layer, to realize the deposition of μc-Si：H films with device-grade quality on cheap substrates such as general glass.
基金Project supported the Key Project of Tianjin Municipal Science and Technology Commission （Grant No 043186511）, the National Natural Science Foundation of China （Grant No 60506003）, and the Chinese-Greece International Project,
文摘Hydrogenated microcrystalline silicon （μc-Si：H） films are fabricated by very high frequency plasma enhanced chemical vapour deposition （VHF-PECVD） at a silane concentration of 7% and a varying total gas flow rate （H2＋SiH4）. Relations between the total gas flow rate and the electrical and structural properties as well as deposition rate of the films are studied. The results indicate that with the total gas flow rate increasing the photosensitivity and deposition rate increase, but the crystalline volume fraction （Xc） and dark conductivity decrease. And the intensity of （220） peak first increases then decreases with the increase of the total gas flow rate. The cause for the changes in the structure and deposition rate of the films with the total gas flow rate is investigated using optical emission spectroscopy （OES）.
文摘采用RF PECVD方法,在P a SiC:H薄膜沉积技术基础上,通过逐步减小碳、硼的掺杂浓度,增大氢稀释率,使材料从非晶态向微晶态转变,在获得本征微晶材料之后,再逐步增大硼掺杂浓度,得到P型微晶硅薄膜材料(暗电导率为5.22×10-3S/cm,光学带隙大于2.0eV)。在这个过程中可以明显观察到碳、硼抑制材料晶化的作用。
文摘采用射频等离子体增强化学气相沉积（RF-PECVD）法在低温、低功率的条件下制备了一系列本征硅薄膜,研究了硅烷浓度（CS）对薄膜微结构、光电特性及表面钝化性能的影响.将本征硅薄膜作为钝化层应用到氢化纳米晶硅/晶硅（nc-Si：H/c-Si）硅异质结（SHJ）太阳电池中,研究了硅烷浓度和薄膜厚度对电池性能的影响.实验发现：随着硅烷浓度的降低,本征硅薄膜的晶化率、氢含量、结构因子、光学带隙和光敏性等都在过渡区急剧变化;本征硅薄膜的钝化性能由薄膜的氢含量及氢的成键方式决定.靠近过渡区的薄膜具有较好的致密性和光敏性,氢含量最高,带隙态密度低,且主要以Si H形式成键,对硅片表现出优异的钝化性能,使电池的开路电压大幅提高.但是,当薄膜的厚度过小时,会严重影响其钝化质量.本实验中,沉积本征硅薄膜的最优硅烷浓度为6%（摩尔分数）,且当薄膜厚度为~8 nm时,所制备电池的性能最好.实验最终获得了开路电压为672 m V,短路电流密度为35.1 m A·cm-2,填充因子为0.73,效率为17.3%的nc-Si：H/c-Si SHJ太阳电池.
