Article

Experimental setup for camera-based measurements of electrically and optically stimulated luminescence of silicon solar cells and wafers.

Institute for Solar Energy Research Hamelin (ISFH), Am Ohrberg 1, 31860 Emmerthal, Germany.
The Review of scientific instruments (Impact Factor: 1.52). 03/2011; 82(3):033706. DOI: 10.1063/1.3541766
Source: PubMed

ABSTRACT We report in detail on the luminescence imaging setup developed within the last years in our laboratory. In this setup, the luminescence emission of silicon solar cells or silicon wafers is analyzed quantitatively. Charge carriers are excited electrically (electroluminescence) using a power supply for carrier injection or optically (photoluminescence) using a laser as illumination source. The luminescence emission arising from the radiative recombination of the stimulated charge carriers is measured spatially resolved using a camera. We give details of the various components including cameras, optical filters for electro- and photo-luminescence, the semiconductor laser and the four-quadrant power supply. We compare a silicon charged-coupled device (CCD) camera with a back-illuminated silicon CCD camera comprising an electron multiplier gain and a complementary metal oxide semiconductor indium gallium arsenide camera. For the detection of the luminescence emission of silicon we analyze the dominant noise sources along with the signal-to-noise ratio of all three cameras at different operation conditions.

0 Bookmarks
 · 
135 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Bulk lifetime and doping images on silicon bricks can be obtained by spectral luminescence intensity ratio analysis as established recently. Here, we report on calibrated full spectrum band-to-band luminescence measurements taken on the flat side faces of mono- and multicrystalline silicon bricks at room temperature. Our results verify the physical modeling used for the spectral intensity ratio imaging. We further investigate three fitting methods employing spectrally resolved photoluminescence data to obtain bulk lifetime information.
    IEEE Journal of Photovoltaics 01/2013; 3(3):962-969. · 3.00 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Classification of defective regions in p-type multicrystalline silicon by comparing luminescence images measured under different conditions Abstract In this contribution, we apply three different camera-based luminescence imaging techniques to mc-Si wafers and solar cells, fabricated on neighboring wafers. On wafer level, we determine the spatially-resolved carrier lifetime using calibrated photoluminescence lifetime imaging. On the solar cell level, we use band-to-band electroluminescence and sub-band-gap electroluminescence imaging for the characterisation. We analyze the differences obtained by the different techniques in specific defective areas. Characteristic regions are additionally examined using deep-level transient spectroscopy (DLTS). Comparing different luminescence images, we find different signal correlations in selected regions of the wafers and the neighboring cells presumably caused by different types of defects, which react more or less effective on the phosphorus gettering during the solar cell process. DLTS spectra show that in the edge region of the wafer close to the crucible, FeB pairs are present in the wafer as well as in the cell. However, the FeB concentration in the cell is, due to phosphorus gettering during the cell process, reduced by one order of magnitude. In regions which appear as very recombination-active defect clusters in the solar cell, we detect ZnB pairs by DLTS analysis. Note that the ZnB itself is a shallow centre and therefore expected to be not strong recombination active. However, our measurements reveal that Zn is present in regions with increased recombination activity, which is also in good agreement with the high total Zn concentration measured in the mc-Si ingot. We hence conjecture that dislocation clusters decorated by Zn are responsible for the non-getterable defect regions.
    Energy Procedia 01/2013; 38:101-107.
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we separate a macroporous silicon absorber from a monocrystalline n-type silicon wafer by means of electrochemical etching. The porosity is (31 ± 3)%. The epitaxial growth of a p +-type Si layer onto one side of the macroporous silicon substrate forms a pn-junction that covers the full outer and inner surface of the macroporous layer. Epitaxy reduces the porosity to (19 ± 2)%. The thickness of the epitaxial layer is (3.0 ± 0.2) μm on the rear side and (0.4 ± 0.1) μm on the pore walls. We process (35 ± 2)-μm-thick macroporous silicon solar cells with an aperture area of 2.25 cm2. The short-circuit current density is 37.1 mA cm-2, and the open-circuit voltage is 544 mV. A fill factor of 65.1% limits the energy-conversion efficiency to 13.1%.
    IEEE Journal of Photovoltaics 04/2013; 3(2):723-729. · 3.00 Impact Factor

Full-text (3 Sources)

Download
101 Downloads
Available from
May 30, 2014