Preparation of High-Quality n-Type Poly-Si Films by the Solid Phase Crystallization (SPC) Method

Abstract

For further improvement of conversion efficiency in a-Si solar cells, it is necessary to develop materials with high photosensitivity in the long-wavelength region. A new solid phase crystallization (SPC) method was developed to grow a Si crystal at temperatures as low as 600°C. Using this method, high-quality thin-film polycrystalline silicon (poly-Si) with a Hall mobility of 70 cm2/V·s was obtained. Quantum efficiency in the range of 800 nm ∼ 1000 nm was achieved up to 80% in an experimental solar cell using the n-type poly-Si with a grain size of about 1.5 µm. Therefore, it was found that our SPC method was suitable as a new technique to prepare high-quality solar cell materials.

Improved conductivity of aluminum-doped ZnO: The effect of hydrogen diffusion from a hydrogenated amorphous silicon capping layer

“…10 Within the field of thin film silicon-based solar cells, poly-crystalline silicon (poly-Si) receives attention because it couples the potential for high conversion efficiency and lower production costs. One of the approaches toward poly-Si is plasma deposition of amorphous silicon followed by solidphase crystallization (SPC), 11,12 which has delivered efficiencies up to 10%; 13,14 for example, CSG Solar 15 has achieved an efficiency of 10.4% by developing a 2.5 lm-thick poly-Si on glass, which was also confirmed by studies reported by Green et al 15 In this case, the TCO can be applied as front contact and aluminum-doped zinc oxide (ZnO:Al) is often referred to as a valid alternative to, e.g., indium tin oxide. The ZnO is considered appealing due to the relatively low cost, high abundance, non-toxicity, 16,17 resistance to H 2 etching, 18,19 and, under specific conditions, surface texturing for light management/trapping.…”

Influence of the Doping Gas on the Axial Uniformity of the Growth Rate and the Electrical Properties of LPCVD In-Situ Doped Polysilicon Layers

“…More recently, its interest increased in the studies concerning solar cells because of its potentially better electrical properties than amorphous silicon which is metastable [2,3]. However, having a weaker absorption, it is necessary either to deposit thicker layers of polysilicon, thus to increase the growth rate, or to deposit it on a very large area.…”

Electrical properties of phosphorus-doped polycrystalline germanium formed by solid-phase and metal-induced crystallization

“…The peak intensity values of SPC and SPC-low samples slightly decrease with increased annealing temperature because of increased self-nucleation spots, subsequently resulting in smaller crystal grain size. For SPC-high samples, high concentration P atoms prevent the formation of self-nucleation sites in Ge [9], resulting in relatively higher XRD peak intensity values than those of SPC and SPC-low samples. The peak intensity of SPC-high sample annealed at 600°C was reduced to the intensity level of SPC and SPC-low samples because self-nucleation process was accelerated due to high dopant loss (>50%) at 600°C.…”