A new type of nano-composite used for back contact layers in CdTe solar cells was studied. Both open-circuit voltage and the fill factor of a CdTe solar cell with the nano-composite back contact layer were improved obviously to 838.5 mV and 70.35%, respectively after the optimization of film composition, deposition method and annealing process. The conversion efficiency of the solar cell has reached up to 14.05%, which shows that it is a promising nano-matetial for back contact layer and further optimization is needed for better performance of solar cells.

The Zinc sulfide(ZnS) thin films are prepared on glass substrate by RF magnetron sputtering technique at different substrate temperatures and Ar gas flows.Characterization of the film properties is carried out using surface probe surface profilometer,ultra-vision/vision(UV/Vis) spectrophotometer and X-ray diffraction(XRD).The results indicate that X-ray diffraction analysis confirms the formation of ZnS sphalerite phase and has strong(111) preferred orientation and great lattice stress at all substrate temperatures.The deposited rates are reduced with the increasing of the substrate temperature.The best thin film is deposited as the substrate temperature is 300℃.The Ar gas flow has great positive correlation influence on deposited rates,but little influence on the optical and microstructure properties.

采用射频磁控溅射法制备了CdTe/ZnTe多层薄膜,并在制备单层CdTe薄膜和ZnTe薄膜的基础上,研究了衬底温度对CdTe/ZnTe多层薄膜性质的影响；通过XRD和透过谱、吸收谱的分析,对其结构进行了研究.结果表明在185℃下制备的CdTe/ZnTe多层膜中,CdTe和ZnTe均沿(111)晶面择优取向生长,尤其是ZnTe沿(111)晶面择优取向明显,衍射强度极大.通过比较不同衬底温度,发现185℃生长的样品衍射峰强度最高,成膜质量较好；通过吸收谱图分析,185℃下沉积的样品对光有较好的吸收性.

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.

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.

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.

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.

Deposition of Sb2Te3 thin films on soda-lime glass substrates by coevaporation of Sb and Te is described in this paper. Sb2Te3 thin films were characterized by x-ray diffraction (XRD), x-ray fluorescence (XRF), atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), electrical conductivity measurements, and Hall measurements. The abnormal electrical transport behavior occurred from in situ electrical conductivity measurements. The results indicate that as-grown Sb2Te3 thin films are amorphous and undergo an amorphous-crystalline transition after annealing, and the posttreatment can effectively promote the formation of Sb-Te bond and prevent oxidation of thin film surface.

AlSb polycrystalline thin films were prepared by cosputtering. The structure, morphology and electrical properties of the films are studied. X-ray diffraction results show that the films are AlSb polycrystalline with a face-centered cubic structure. The use of hydrogen in the atmosphere and the higher substrate temperature are beneficial to the grain growth of the AlSb films. The intrinsic AlSb film is p-type semiconductor with the conductivity activation energy of 0.32 eV and 0.25 eV.

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.

In 2 O 3 ∶SnO 2 （ITO） thin films were fabricated on the substrate of flexible polyethylene terephthalate（PET） by DC magnetron sputtering from a ceramic target of In 2 O 3 /SnO 2 （90∶10）. Properties of the thin films were characterized by X-ray diffraction（XRD）, four-point probe, Hall-effect measurement, UV-Vis spectrophotometer, and scanning electron microscopy（SEM）. The effects of sputtering pressure, oxygen partial pressure and deposition temperature on properties of microstructure and optoelectronics properties of PET/ITO thin films were investigated in detail. High-quality ITO thin films on PET substrates with the resistivity as low as 8.5×10-4 Ω·cm and the optical transmittance over 80% in the visible spectrum range were obtained.

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.

ZnS thin films were prepared on glass substrate by RF magnetron sputtering technique.The quality of ZnS films formed at different deposition pressures,annealing temperatures and substrate temperatures were studied.The change of the film microstructure was analyzed by XRD and the lattice stress was evaluated.The spectral transmittance was measured by a spectrometer.From the spectrum,the band gap and Urbach energy were calculated.Scanning electron microscopy (SEM) was used to study the morphology of the surface of the sample.The result showed that there is big stress in the lattice when the substrate is at room temperature,and the value of stress increases with the pressure.After annealing at 300 ℃,the stress is minimal.When the substrate temperature is 350 ℃,the stress decreases,at the same time,ZnS films have good transmittance,and annealing at 300 ℃ improves the film quality.

CdS:Cu thin films were prepared using a vacuum co-evaporation technique. The Hall measurements indicate that the conductivity characteristic of CdS thin films transformed from highly compensated in as-grown or weakly annealed materials to p-type conductive in strongly annealed materials. X-ray diffraction spectra show that as-deposited thin films were the hexagonal phase of CdS except the presence of copper for high Cu doping and the diffraction peaks of Cu disappeared after annealing. From the X-ray photoelectron spectroscopy we found the ionization of Cu atoms and the formation of an acceptor level. In situ dark conductivity in vacuum as-deposited CdS:Cu was performed in the temperature range between 27 and 250°C. An abnormal temperature dependence of conductivity was observed in medium and heavily Cu-doped films. The formation of a p-type material at a certain temperature was also studied by the hot probe measurements, which indicates a complex compensation process in the Cu-doped CdS films.

Indium-tin-oxide(ITO) films were deposited on glass substrate by DC magnetron sputtering.The effects of DC power and oxygen partial pressure on the microstructure,electrical and optical properties of the ITO thin films were studied by four-point probe,X-ray diffraction(XRD),UV-vis spectrometer,hall measurement and scanning electrical microscope(SEM).The results showed that the films had a preferred orientation in the(222) plane.DC power had little influence on the optoelectrical properties of the ITO films and the deposition rate increased with the increase of DC power.As oxygen partial pressure increased,the Hall mobility of the films increased initially and then decreased while the charge carrier concentration decreased and the resistivity increased.As a result,ITO films with a resistivity of 1×10-4Ω·cm,and an average transmittance of 85% in the visible spectrum were deposited successfully.