Atheta (Parameotica) difficilis Bris. (rigua Williams) ist eine gute Art

Volume: 88Start Page: 561End Page: 56

Atheta lazorkoi n. sp. (Coleoptera: Staphylinidae) aus der Ukraine

Volume: 92Start Page: 299End Page: 30

Neue Atheten (Col., Staphylinidae) aus dem Mus\ue9um d\u27Histoire naturelle in Genf

Volume: 88Start Page: 297End Page: 30

High efficiency n-type silicon solar cells with front side boron emitter

High-efficiency n-type PERL solar cells with a front side boron emitter passivated by ALD Al2O3 are presented within this work. For the applied PERL cell design two variations have been employed: i) different boron emitters (deep / shallow) and ii) different dielectric layers for rear side passivation (thermal grown SiO2 and PECVD SiNx). Both, thermal grown SiO2 as well as PECVD SiNx provide an effective passivation of the n-type rear surface with effective surface recombination velocities of 4 cm/s and 7 cm/s respectively. If the metalized rear side point contacts (with BSF) together with the recombination of the 1 O cm FZ base silicon are taken into account this results in saturation current densities of 30 fA/cm2 and 37 fA/cm2 respectively, limiting the open-circuit voltage (all recombination losses due to the front side are neglected) to 717 mV and 712 mV. The passivation of the boron emitter with ALD Al2O3 results in an emitter saturation current density as low as 11 fA/cm2. Together with the losses at the rear side as well as the front side contacts this allows for an open-circuit voltage of the applied PERL solar cell design of ~700 mV. For n-type PERL solar cells featuring a lowly doped boron emitter as well as a SiO2 passivated rear such a high open-circuit voltage (up to 703.6 mV) could be reached also at the device level, resulting in a conversion efficiency of 23.4%. Also for the PERL solar cells featuring a high surface concentration boron emitter with a PECVD SiNx passivated rear, i.e. first steps towards an industrial structure, still a high conversion efficiency of 21.8% could be achieved. All cells have been shown to be perfectly stable under illumination at 1 sun

Status and prospects of Al2O3 –based surface passivation schemes for silicon solar cells

The reduction in electronic recombination losses by the passivation of silicon surfaces is a critical enabler for high-efficiency solar cells. In 2006, aluminum oxide (Al2O3) nanolayers synthesized by atomic layer deposition (ALD) emerged as a novel solution for the passivation of p- and n-type crystalline Si (c-Si) surfaces. Today, high efficiencies have been realized by the implementation of ultrathin Al2O3 films in laboratory-type and industrial solar cells. This article reviews and summarizes recent work concerning Al2O3 thin films in the context of Si photovoltaics. Topics range from fundamental aspects related to material, interface, and passivation properties to synthesis methods and the implementation of the films in solar cells. Al2O3 uniquely features a combination of field-effect passivation by negative fixed charges, a low interface defect density, an adequate stability during processing, and the ability to use ultrathin films down to a few nanometers in thickness. Although various methods can be used to synthesize Al2O3, this review focuses on ALD—a new technology in the field of c-Si photovoltaics. The authors discuss how the unique features of ALD can be exploited for interface engineering and tailoring the properties of nanolayer surface passivation schemes while also addressing its compatibility with high-throughput manufacturing. The recent progress achieved in the field of surface passivation allows for higher efficiencies of industrial solar cells, which is critical for realizing lower-cost solar electricity in the near future