Université de Neuchâtel

Preparation of undoped and doped microcrystalline silicon(μc-Si:H) by VHF-GD for p-i-n solar cells

Flückiger, R. ; Meier, Johannes ; Keppner, Herbert ; Goetz, M. ; Shah, Arvind

In: Conference Record of the 23th IEEE Photovoltaic Specialists Conference, 1993, p. 839-844

The electronic transport properties of μc-Si:H materials were investigated. The μc-Si:H was deposited by the very high frequency-glow discharge (VHF-GD) technique at an RF-excitation of 70 MHz. Very thin

doped layers (100-400 Å) were studied. Conductivities higher than 10-3 (Ω cm)-1 could be achieved for films thicker than 150 Å. The as-deposited μc-Si:H is a slightly...

Université de Neuchâtel

Intrinsic microcrystalline silicon (μc-Si:H)-a promising newthin film solar cell material

Meier, Johannes ; Dubail, S. ; Flückiger, R. ; Fischer, Diego ; Keppner, Herbert ; Shah, Arvind

In: Conference Record of the Twenty Fourth IEEE Photovoltaic Specialists Conference (1994 IEEE First World Conference on Photovoltaic Energy Conversion), 1994, vol. 1, p. 409-412

“Compensated” microcrystalline silicon is obtained by adding 8-20 ppm diborane in the plasma gas phase. p-i-n cells with such i-layers have increased infrared sensitivity when compared to a-Si:H p-i-n cells. The preparation of the world's first “mixed stacked” a-Si:H/μc-Si:H tandem cell with an initial efficiency of 9.1% is reported. The μc-Si:H cells showed no degradation of the cell...

Université de Neuchâtel

Enhanced optical absorption in microcrystalline silicon

Beck, N. ; Meier, Johannes ; Fric, J. ; Remeš, Z. ; Poruba, A. ; Flückiger, R. ; Pohl, J. ; Shah, Arvind ; Vaněček, Milan

In: Journal of Non-Crystalline Solids, 1996, vol. 198-200, p. 903-906

An enhanced optical absorption, compared to crystalline silicon, was observed in the above gap region together with very low defect-connected absorption in microcrystalline silicon (μc-Si:H) prepared by very high frequency glow discharge technique at 70 MHz. As the μc-Si:H material has a very low fraction of amorphous phase, a ‘crystalline silicon like’ absorption model is proposed which...

Université de Neuchâtel

Towards high-efficiency thin-film silicon solar cells with the “micromorph” concept

Meier, Johannes ; Dubail, S. ; Platz, R. ; Torres, Pedro ; Kroll, U. ; Anna Selvan, J. A. ; Pellaton Vaucher, N. ; Hof, Ch. ; Fischer, D. ; Keppner, Herbert ; Flückiger, R. ; Shah, Arvind ; Shklover, V. ; Ufert, K. -D.

In: Solar Energy Materials and Solar Cells, 1997, vol. 49, no. 1-4, p. 35-44

Tandem solar cells with a microcrystalline silicon bottom cell (1 eV gap) and an amorphous-silicon top cell (1.7 eV gap) have recently been introduced by the authors; they were designated as “micromorph” tandem cells. As of now, stabilised efficiencies of 11.2% have been achieved for micromorph tandem cells, whereas a 10.7% cell is confirmed by ISE Freiburg. Micromorph cells show a rather low...

Université de Neuchâtel

Complete microcrystalline p-i-n solar cell—Crystalline or amorphous cell behavior?

Meier, J. ; Flückiger, R. ; Keppner, H. ; Shah, Arvind

In: Applied Physics Letters, 1994, vol. 65, no. 7, p. 860-862

Complete µc-Si:H p-i-n solar cells have been prepared by the very high frequency glow discharge method. Up to now, intrinsic µc-Si:H has never attracted much attention as a photovoltaic active material. However, an efficiency of 4.6% and remarkably high short circuit current densities of up to 21.9 mA/cm2 due to an enhanced absorption in the near-infrared could be...

Université de Neuchâtel

Device grade microcrystalline silicon owing to reduced oxygen contamination

Torres, P. ; Meier, J. ; Flückiger, R. ; Kroll, U. ; Anna Selvan, J. A. ; Keppner, H. ; Shah, Arvind ; Littlewood, S. D. ; Kelly, I. E. ; Giannoulès, P.

In: Applied Physics Letters, 1996, vol. 69, no. 10, p. 1373-1375

As-deposited undoped microcrystalline silicon (µc-Si:H) has in general a pronounced n-type behavior. Such a material is therefore often not appropriate for use in devices, such as p-i-n diodes, as an active, absorbing i layer or as channel material for thin-film transistors. In recent work, on p-i-n solar cells, this disturbing n-type character had been...

Université de Neuchâtel

Electrical properties and degradation kinetics of compensated hydrogenated microcrystalline silicon deposited by very high-frequency-glow discharge

Flückiger, R. ; Meier, J. ; Goetz, M. ; Shah, Arvind

In: Journal of Applied Physics, 1995, vol. 77, no. 2, p. 712-716

Microcrystalline silicon (µc-Si:H) layers deposited by the very high-frequency-glow discharge technique at a radio-frequency excitation of 70 MHz are observed to be basically slightly n type. By doping (so-called ``microdoping'') with boron in the gas phase volume part per million (vppm) range, compensated material could be obtained. The influence of this doping on the electronic...