CdS polycrystalline thin films were prepared by close-space sublimation,and then the films were treated at 400 ℃ for Cl-doping.The electrical properties of CdS before and after doping were studied by analyzing the relationship of light/resistance and dark resistance/ temperature.The results show that,under the lighting with different wavelengths,the films have different resistances,and the minimum resistance appears in the vicinity of 500nm wavelength;in the conversion process of dark and light,the effects of doping on the resistance time relaxation are greater;after doping,the dark conductivity increases while activation energy decreases.

It is well known that preparing temperatures and defects are highly related to deep-level impurities. In our studies, the CdTe polycrystalline films have been prepared at various temperatures by close spaced sublimation (CSS). The different preparing temperature effects on CdS/CdTe solar cells and deep-level impurities have been investigated by I—V and C—V measurements and deep level transient spectroscopy (DLTS). By comparison, less dark saturated current density, higher carrier concentration, and better photovoltaic performance are demonstrated in a 580°C sample. Also there is less deep-level impurity recombination, because the lower hole trap concentration is present in this sample. In addition, three deep levels, Ev + 0.341 eV(H4), Ev + 0.226 eV(H5) and EC − 0.147 eV(E3), are found in the 580°C sample, and the possible source of deep levels is analysed and discussed.

采用超声喷雾热解法制备了SnS薄膜,用XRD和SEM等测试手段对薄膜样品的晶体结构和表面形貌进行了表征,并测试了SnS薄膜时光学性能.制备中对比了几种反应前驱液配方和改变沉积温度对SnS薄膜结构、形貌及透过率的影响,得到了如下结果:以N,N-二乙基硫脲+氯化亚锡+甲醇溶液作为前驱液,沉积温度为300℃时,可得到不含有SnO2的单一SnS薄膜.

The CdTe thin films PV module had been studied by measuring the contact resistance between the back contact metal and the front TCO film of the adjacent elementary cells.The "MODULE DESIGN SIMULATOR" software had been used to simulate the effects of the film electronic performance,the integration structure,and the contact elementary cell characteristics on module characteristics.The contact resistance decreases with the increasing of the thickness of Ni film.And the contact resistance increases 1-2 orders of magnitude when the CdTe films were etched by basic frequency laser.The highest efficiency corresponds with the optimized cell width and the width of the notches.The unit cell width,sheet resistance of TCO & CdTe,and TCO/Ni contact resistance have great effect on the property of the module,respectively.With the increasing of TCO sheet resistance,the conversion efficiency firstly increase sharply and then decrease slowly.Increasing the sheet resistance of CdTe will lead to the increasing of both conversion efficiency and fill factor.

制备高效的CdTe太阳电池,改善电池的背接触特性是一关键技术.背接触层中掺Cu能够得到性能良好的电池,但Cu在CdTe中进一步扩散,会形成缺陷,造成CdTe太阳电池性能不稳定.因此,有必要系统研究Cu原子在薄膜中的存在状态,进而有效控制Cu的浓度;另一方面,要获得良好的背接触层,必须制备出结构致密的ZnTe与五ZnTe:Cu多晶薄膜.研究了衬底温度及沉积速率的变化对ZnTe:Cu薄膜质量及电池性能的影响.在常温下沉积ZnTe后,提高衬底温度沉积ZnTe:Cu对太阳能电池的影响明显,得到了转化效率达10.28%的电池.

In this paper, the AlSb polycrystalline thin films were prepared by vacuum co-evaporation technology and their structural, optical and electrical properties have been studied. XRD results showed that the as-deposited AlSb amorphous thin films transformed to polycrystalline state after annealed in vacuum at temperatures higher than 540°C. The process of phase change was observed to depend on the annealing temperature and the film composition. Some irreversible changes took place in the annealed films during the measurement of the temperature dependence of the film conductance. The conductance activation energy of the film was 0.132 and 0.32 eV during the heating and cooling process, respectively, which suggests the decrease of Sb vacancies in the AlSb film after the heating. Hall effect and optical absorption measurement showed that the AlSb polycrystalline thin films were p-type, indirect bandgap semiconductors with absorption coefficient higher than 8 × 104 cm -1. TCO/CdS/AlSb photovoltaic devices with the local open circuit voltage of over 200 mV have been fabricated.

In this paper,the CdS thin films deposited by close-spaced sublimation have been annealed. The properties of films were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM) and the relationship of dark conductivities～temperature(σ～T).The results showed that(002) preferred direction of crystalline grains still exists after annealing;the treatment can promote recrystallization and grain growth;With the annealing temperatures increasing,the dark conductivities(σ-dark) increase while the dark conductivity activation energy(Ea) decreases.Finally,an optimization anneal condition has been achieved and the CdS thin films as windows layers of CdTe solar cells have been obtained.

In the present paper, SnS thin films were deposited by ultrasonic spray pyrolysis method. The influence of the three different precursor concentrations on the properties of SnS thin films was compared. XRD shows that when precursor solution is thiourea (0.5 mol x L(-1)) + tin tetrachloride (0.5 mol x L(-1)) + deionized water, there are SnS and SnO2 mixed phases; when precursor solution is thiourea (0.6 mol x L(-1)) + tin tetrachloride (0.5 mol x L(-1)) + deionized water, SnS phase is the dominant diffraction peak, although a certain amount of SnO2 phase is contained; when precursor solution is thiourea (0.7 mol x L(-1)) + tin tetrachloride (0.5 mol x L(-1)) + deionized water, thin film after being annealed is single SnS thin film with orthorhombic structure. SEM shows that films are uniform and dense. Furthermore, the particles of films are bigger when thiourea concentration is higher. Transmittance spectrum shows that the influence of precursor concentration on transmittance of thin films is less. Dark I-V and C-V tests of the devices show that junction characteristics of the devices were similar when prepared by three different concentrations of precursor solution, and as the thiourea concentration is higher, the carrier concentration is relatively larger.

我们采用等离子束轰击的方法,研究了干法腐蚀对多晶CdTe薄膜结构和性能的变化,以及对CdTe太阳电池性能的影响.发现与湿法腐蚀方法相比,等离子束溅射轰击不仅可以彻底清除表面的氧化层,而且可以同时改善表面的微粗糙度,增强薄膜的附着力.通过对不同腐蚀方法所制成的CdTe电池器件的性能测试,得出了电池性能较好的干法腐蚀工艺条件.

CdS polycrystalline thin films were fabricated by magnetron sputtering and the influence of substrates, sputtering powers, pressures, and substrate temperatures on the structure of thin films is investigated. The films deposited on substrates of glass, quartz, SnO2: F and p-type single silicon are hexagonal phase and they grow preferentially along (002) planes. As the radio-frequency power and substrate temperature increase, the preferential growth is improved, while it is decreased with the increases of pressure especially over 0.2 Pa. In addition, annealing in air or N2 or with CdCl2 can increase the grain size greatly and promote preferential growing.

The Al-Sb multi-layer films were prepared by magnetron sputtering method,and that samples of different atomic ratio were obtained through adjustment of Al and Sb sub-layer thickness and number,and then annealed in vaccum.The structural and electrical properties of the films before and after annealing have been studied with X-ray diffraction (XRD),X-ray fluorescence (XRF),scanning electron microscope (SEM),Metallogragh,Hall effect and Auger electron spectrometer.The results showed that only the Sb peaks were observed in as-deposited films.After annealing at 500℃,the P-type AlSb ploycrystalline films were obtaied by combination of Al and Sb elements,and with (111) preferred orientation.Also,the samples occurred partial damage in excess of 600℃ annealing.The deliquescence phenomenon of films was observed and analyzed with step profiler microcamera and auger depth profilling,and gives some methods to improve.

The Al/Sb multi-layer thin films were prepared by magnetron sputtering method. The structural, optical and electrical properties of the films before and after annealing have been studied with X-ray diffraction (XRD), X-ray fluorescence (XRF), Hall effect, the temperature dependence of the film dark conductivity and UV-Vis transmission spectra. The XRD results showed that only the Sb polycrystalline peaks were observed in as-deposited films while Al existed in amorphous state. After annealing at 500℃, the films showed AlSb peaks with (111) preferred orientation, which suggested that Al and Sb atoms have combined to form AlSb by interdiffusion. The measurement results of Hall effect indicated that the prepared AlSb films were p-type semiconductors with the carrier concentration of 1019cm-3. The energy band-gap of the AlSb films obtained from UV-Vis data were about 1.64eV. The temperature dependence of the film conductivity showed two stages. In the heating process from 30℃ to 110℃, the conductivity of the film increased slowly with the temperature. In the stage from 110℃ to 260℃, the film conductivity increased more quickly with the temperature. The calculated conductivity activation energy was 0.01eV and 0.11eV, respectively. This result had close relationship with the structural changes of the multi-layer Al/Sb films in the heating process. The obvious photovoltaic effect has been observed in TCO/CdS/AlSb/ZnTe:Cu/Au devices, which demonstrated the potential of AlSb as the absorber layer in solar cells.

Cu would be doped and form deep level centers easily in CdTe solar cells. The deep level centers in ZnTe back contact and graphite back contact CdTe solar cells were studied by deep level transient spectroscopy(DLTS). The electronic density of states on zinc blende CdTe，VCd system and CdTe doping Cu were analyzed with density functional theory. The d-orbital splitting of Cu2+ in C3v and Td fields was obtained. The results show that two deep centers Ev+0206 eV and Ev+0122 eV，respectively，are attributed to substitutional Cu，energy of CdTe is reduced after Cu doping，and Cu could replace Cd.

本文测试了掺杂石墨浆作背接触层的CdTe薄膜太阳电池的导纳谱,计算得到电池中存在的影响电池性能的缺陷能级及其俘获截面.掺杂石墨浆作背接触层的CdTe薄膜太阳电池中存在三个缺陷能级,其位置E1-Ev分别约为0.34,0.46和0.51 eV,对应的俘获截面分别为2.23x10(-16),2.41x10(-14),4.38x10(-13)cm2.

Polycrystalline CdTe thin films were prepared by close-spaced sublimation (CCS) and were annealed in different condition. The thin films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy(XPS). The content distribution and valence state of all elements after annealing were studied. All results show that the as-deposited CdTe thin films are in a cubic phase and have the preferred orientation in (111) direction. After annealing, the peak intensity of (111), (220), (311) grows and the crystal grains grow up, while the crystal boundary decreases. So the compound probabilities of current carrier decrease, therefore shunt resistance and drain current are improved. From detailed analysis of X-ray photoelectron data, it is proposed that tellurium oxides present and its content reduces with depth increasing and that there are TeCl2O building blocks.

In this research, the CdTe polycrystalline films are prepared at various temperatures by close-spaced sublimation. The experiment was conducted to investigate how difference in preparation temperature effects on CdTe/CdS solar cells by the characteration of I - V , C - V curves and deep level transient spectroscopy. The result shows that the difference of temperatures has some effect on I sc and FF, but not on V oc . The samples prepared at 580℃ have lowest dark saturated current density, higher carrier concentration and the photovoltaic performance is preferable. The response of deep-level impurities in CdTe films is unchanged with temperature and frequency, but the sample prepared at 580℃ has less deep-level impurity recombination because of lower hole trap concentration. Then, the CdS/CdTe solar cells with large area of 300 mm×400 mm have efficiency reaching 82% by improving the uniformity of temperature field.

CdTe thin film solar cells with a doped-graphite paste back contact layer were studied using admittance spectroscopy technology. The positions and the capture cross sections of energy level in the forbidden band were calculated, which are the important parameters to affect solar cell performance. The results showed that there were three defects in the CdTe thin films solar cells with the doped-graphite paste back contact layer, whose positions in the forbidden band were close to 0.34, 0.46 and 0.51 eV, respectively above the valence band, and capture cross sections were 2.23×10 −16 , 2.41×10 −14 , 4.38×10 −13 cm 2 , respectively.

CuxTe polycrystalline thin films were prepared by co-evaporation method. The influence of the film characteristic on the CdS/CdTe photovoltaic device performance was investigated. The results show that asdeposited CuxTe thin films are amorphous phase. While after annealing, samples were polycrystalline phases with increasing temperature. Especially, when NCu:NTe was 1:1.44 the film showed more evident polycrystalline phase and the crystallization degree increased. Furthermore, Cu and Te elements of the annealed films form ions from XPS analysis. The C-V, I-V characteristics indicate that the CuTe buffer layers eliminate the Roll Over phenomenon. Meanwhile, the back contact properties, such as the diode characteristics (A) of the forward junction and the dark saturation current density (Jsc) have been improved. As a result, the conversion efficiency is improved by 14.5%, from 10.3% to 12.667%.

The multilayer Al/Sb thin films were deposited on quartz glass substrates using magnetron sputtering method and annealed at high temperature to obtain AlSb films. The experimental conditions were optimized to obtain the AlSb single phase. XRD measurements indicate that high-temperature annealing is necessary to form AlSb and is helpful to the grain growth of AlSb polycrystalline. The average grain size of AlSb polycrystalline increases obviously with the increase in annealing temperature when higher than 500°C. The electrical measurements show that the prepared AlSb films are p-type semiconductors with the conductivity activation energy of 0.21 and 0.01eV. The optical band gap for a typical AlSb film is 1.76eV. The obvious photovoltaic effect has been observed in TCO/CdS/AlSb/ZnTe:Cu/Au devices, which demonstrated the potential of AlSb film as the absorber layer in thin film solar cells.

对近空间升华法制备的大面积(30×40 cm~2)CdTe多晶薄膜用不同方法进行退火处理,用XRD、C～V、I～V等研究了退火条件,退火方式对薄膜结构和器件性能的影响.结果表明:刚沉积的CdTe多晶薄膜呈立方相,沿着(111)方向择优取,向而退火后(111)(220)(311)等峰都有不同程度的增加.在纯氧气氛下,400℃退火还出现了新峰.随着退火温度的增加,电导激活能降低.经过连续退火装置在400℃下退火30分钟的电池,1/C~2和V成线性关系,具有较高的掺杂浓度、较理想的二极管因子和较高的转换效率.