A.G. Ulyashin

Hydrogen Release and Defect Formation During Heat Treatments of SiNx:H/a-Si: H Double Passivation Layer on C-SI Substrate

The quality and temperature stability of surface passivation of silicon by a double layer consisting of a hydrogenated amorphous silicon thin film capped by a silicon nitride anti-reflection coating are studied. It is established that the passivation effect of the double layer can be significantly enhanced after short annealing for temperatures up to about 500degC, whereas annealing at higher temperatures results in degradation of the passivation properties. It is found that the increased effective recombination lifetime after annealing at temperatures below 500degC results from hydrogen redistribution in the interface region. Furthermore, presence of interfacial structural defects formed due to hydrogen release at temperatures around 600degC, is believed to be the cause of the lifetime decrease after heat treatments at higher temperatures

Formation of Nano-Structures on ITO Antireflection Coating by Hydrogen Plasma Treatments

Recently, low dimensional semiconductor structures such as metallic nanoparticles, have attracted significant attention for photovoltaics. In this work we study the low-temperature formation of metallic nano-dots in an indium tin oxide (ITO) antireflection coating for solar cells after an appropriate hydrogen plasma treatment. Atomic force microscopy (AFM), scanning spreading resistance microscopy (SSRM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used for the analysis of the morphology, electrical properties and composition of ITO layers deposited on Corning glass at different temperatures and subsequently subjected to hydrogen plasma. Formation of highly conductive nano-structures at hydrogenation temperatures below 250degC is observed. It is shown that the nano-structures formation can be controlled by the time and the temperature of the hydrogenation

Shunt detection and characterization with fluorescent microthermal imaging

Defects originating from the solar cell substrate material or created during the solar cell production process can act as parasitic resistances. These defects reduce the performance of solar cells and can in extreme cases cause serious reliability problems in finished solar modules. Some defects will generate heat locally when a bias voltage is applied to the solar cells. Thermal imaging techniques can therefore be used to obtain information about the location, and hence the origin, of such defects. In this work, fluorescent microthermal imaging (FMI) is used to characterize shunted crystalline silicon solar cells. After an introduction to the technique, the suitability of FMI for solar cell diagnostics is demonstrated

Texturing Mechanism of Si using Hydrogen Radicals

A new way of inverted pyramid or labyrinth V groove texture fabrication on the polished silicon surface by the hot filament method is proposed. The assist of mesh like particle layer deposition, which works as an etching mask against hydrogen radical, enables the fabrication of surface texture. The particles were not deposited as mesh like pattern when the SiO2/Si substrate was used. In addition, the particle deposition pattern depended on the substrate area size and the distance between the substrate and the filament. The results suggest that the evaporation of silicon hydrides from the silicon surface has an important role to generate the particles and mesh-like particle pattern. The surface texturization of the EFG ribbon wafers and as cut CZ wafers were examined