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32nd European Photovoltaic Solar Energy Conference and Exhibition; 850-853, The goal of this work is to demonstrate that heterojunction ITO/Si based solar cells fabricated by non-vacuum spray pyrolysis technique for deposition of indium-tin-oxide (ITO) based layers, can be considered as a promising approach for the cost effective processing of ITO/n-type Si based solar cells. It is established that preparation of an intermediate layer between ITO and Si is a crucial step, which determines efficiencies of ITO/Si based solar cells. Two approaches for the formation of such buffer layer have been considered: (i) chemical etching, which results in a formation of a thin Si porous/ sponge-like ITO/Si interface layer and (ii) low- temperature (~450 C) anneals, which result in a formation of a thin SiOx layer at the ITO/Si interface. A set of analytical characterization methods (SEM, TEM, EELS, EDS) have been used for the analysis of individual ITO layers as well as ITO/Si interfaces. It is established that formation of an ultra-thin SiOx layer at the ITO/Si interface is the most promising route to fabricate heterojunction ITO/Si solar cells with the reasonable (above 14%) efficiencies at a low-cost. General technological trends, which lead to an improvement of the conversion efficiency of ITO/Si solar cells, as well as further steps for optimization and improvement of the low-cost processing routes for ITO/Si solar cells are discussed.

Thin films of amorphous SiC were prepared by non reactive magnetron sputtering in an Ar atmosphere. A previously synthesized SiC was used as a solid state target. Deposition was carried out on a cold substrate of p Si 100 with a resistivity of 2 Ohm amp; 61655;cm. The Raman spectrum shows a dominant band at 982 cm 1, i.e. in the spectral region characteristic for SiC. The film thickness determined from atomic force microscopy measurements was about 8 40 nm, the height of the structural units of the film was 1 2 nm, while the linear dimensions were of the order of tens of nanometers. The amorphous nature of SiC grown on the Si substrate is confirmed by the presence of the diffraction rings which indicate the absence of the dominant orientation of the prepared films. A heterostructure consisting of a p type Si 100 and a layer of amorphous n type SiC was fabricated and studied. The investigation of its electrical and photoelectric properties shows that the entire space charge region is located in Si. This is in addition confirmed by the spectral dependence of the p Si n SiC photo sensitivity. The barrier height at the p Si n SiC interface estimated from dark I V characteristics is of the order of 0.9 1.0 eV. Load I V characteristics of p Si n SiC amorphous nanolayer solar cells demonstrate under standard AM1.5 illumination conditions a conversion efficiency of 7.22

26th European Photovoltaic Solar Energy Conference and Exhibition; 2288-2291, The optimization ways and related photovoltaic parameters of the mono- and bi-facial solar cells based on n+ITO-SiO2-nSi isotype structures are presented. A technique for texturing the surface of silicon wafers oriented in (100) plane to form a regular pattern of inverted pyramids as well as irregular topography patterns was developed. The efficiency of the solar cells with monofacial sensitivity from silicon wafers with the surface patterned in the form of inverted pyramids was increased from 10.1 to 15.8%, which is by more than 5% higher compared to the efficiency of the solar cells with unstructured silicon surface. For solar cells with bifacial sensitivity, the total efficiency was increased from 12.6 to 15.7% for the case of irregular patterned silicon surface and up to 20.9% in the case of the regular patterned silicon surface. The developed and applied technique for the structurization of the surface of silicon wafers for solar cell devices resulted in an efficiency increase to up to 15.8% for monofacial and up to 20.9% for bifacial solar cells.

24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 2230-2232, Solar cells fabricated on the basis of semiconductor-insulator-semiconductor (SIS) structures were obtained by the deposition of transparent conductive oxide ITO films onto silicon crystal substrates by spray pyrolisys technique. The obtained in such a way structures may be considered as Schottky diodes with a thin insulating SiO2 layer at the interface formed during the ITO layer deposition. The above mentioned method has been used for the fabrication of solar cells with 9.57% efficiencies under standard AM 1.5 conditions. Bifacial solar cells with a back surface field region at the rear contact were also fabricated. In this case the efficiencies are 9.47% and 3.6% for the front and rear side illumination, respectively. The investigation of I-V characteristics shows that in n+ITO/SiO2/nSi structures two mechanisms of the direct current flow are present: (i) tunneling-recombination at direct voltages of less than 0.3 V and (ii) over-barrier emission at voltages higher than 0.3 V. In the first case, the direct current flow could be interpreted as multi-steps tunnelrecombination transitions of electrons from the silicon conduction band into ITO conduction band, the number of steps being about 100. The calculated potential barrier height at the ITO-Si interface is about 0.6 eV, which is in good agreement with the experimental data.

The influence of thermal treatment in H2 on the parameters of In/nITO/pInP/Ag:Zn solar cells obtained by ITO layers pyrolithic pulverization have been investigated. TheITO/pInP heterostructures obtaining take place at the temperature of 4500 C. As a result of these investigations it was shown that the thermal treatment of In/nITO/pInP/Ag:Zn SC in H2 at 3500 C during 10min leads to the considerable improvement of their photoelectric parameters. The photoelectric parameters of the best solar cell received on InP wafers with concentration p=3∙1017cm-3 after the thermal treatment are Voc=0,626V, Isc=22,72mA/cm2 , FF=71%, Eff=10,09%., У роботі вивчений вплив відпалу в атмосфері водню на параметри сонячних елементів, отриманих піролітичною пульверизацією шарів ІTO на монокристалічних підкладках pInP при температурі 450о С. В результаті проведених досліджень показано, що відпал сонячнихелементів In/nITO/pInP/Ag:Zn у Н2 при температурі 3500 C протягом 10 хв. веде до значного поліпшення їхніх фотоелектричних властивостей. Параметри сонячних елементів, отриманих на підкладках pInP з концентрацією носіїв заряду p=3∙1017cm-3, після термообробки в Н2 досягають наступних значень: Vхх=0,626В, Iкз=22,72мA/cм2, FF=71%, к.к.д.=10,09%., В работе изучено влияние отжига в атмосфере водорода на параметры солнечных элементов, полученных пиролитической пульверизацией слоев ITO на монокристаллические подложки pInP при температуре 450о С. В результате проведенных исследований показано, что отжиг солнечных элементов In/nITO/pInP/Ag:Zn в Н2 при температуре 3500 C в течении 10 мин ведет к значительному улучшению их фотоэлектрических свойств. Параметры солнечных элементов, полученных на подложках pInPс концентрацией носителей заряда p=3∙1017cm-3, после термообработки в Н2 достигают следующих значений: Vхх=0,626В, Iкз=22,72мA/cм2, FF=71%, к.п.д.=10,09%.