[show abstract][hide abstract] ABSTRACT: The goal to achieve grid parity for photovoltaics in the near future is stimulating the development of high efficiency solar cell technologies which has spark off strong activities in silicon heterojunction solar cell development in the recent past leading to a number of high efficiency devices at or beyond 20% efficiency in different laboratories. Heterojunction silicon solar cells show interesting properties which are distinct from those of standard crystalline silicon solar cells due to the combination of thin film and crystalline cell technologies. This paper focuses on device properties of the heterojunction technology (HJT) cell developed at Roth & Rau such as temperature and irradiation dependent performance and cell stability under accelerated stress tests. The results demonstrate an improved energy yield of the Roth & Rau HJT cells that is to be expected under realistic operation conditions.
[show abstract][hide abstract] ABSTRACT: Silicon heterojunction solar cells have high open-circuit voltages thanks to excellent passivation of the wafer surfaces by thin intrinsic amorphous silicon (a-Si:H) layers deposited by plasma-enhanced chemical vapor deposition. We show a dramatic improvement in passivation when H2 plasma treatments are used during film deposition. Although the bulk of the a-Si:H layers is slightly more disordered after H2 treatment, the hydrogenation of the wafer/film interface is nevertheless improved with as-deposited layers. Employing H2 treatments, 4 cm2 heterojunction solar cells were produced with industry-compatible processes, yielding open-circuit voltages up to 725 mV and aperture area efficiencies up to 21%.
[show abstract][hide abstract] ABSTRACT: Silicon heterojunction technology (Si-HJT) consists of thin amorphous silicon layers on monocrystalline silicon wafers and allows for photovoltaic solar cells with energy-conversion efficiencies above 20%, also at industrial-production level. This article reports how this may be achieved. First, we focus on the surface-passivation mechanism of intrinsic and doped amorphous silicon films in such solar cells, enabling record-high values for the open-circuit voltage. Next, the industrial upscaling in large-area reactors of such film deposition is discussed, including the fabrication of solar cells with energy-conversion efficiencies as high as 21%.
Solid-State and Integrated Circuit Technology (ICSICT), 2010 10th IEEE International Conference on; 12/2010