LOANA

Solar Cell Analysis System


The LOANA system is an offline tool for the automated analysis of crystalline silicon solar cells. It combines the most important techniques in one machine.



JV
Combines advantages of Xe-flash and steady state illumination
  • Short circuit current from Xe-flash (& EQE)
  • IV-curve tracing with LED-array
  • Jsc-Voc-characteristics
  • Automatic evaluation for J01, J02, Rs, Rsh

IQE
EQE & reflectance:
  • Full-area measurement by scanning (square 2 x 2 cm² light spot from grating monochromator)
  • Motorized focussing to 1 x 3 mm spot
  • Automatic calibration
  • Automatic determination of bias light intensity

CV
Base doping concentration:
  • Capacitance-voltage measurement near V=0
  • Classic evaluation from slope of graph 1/C²vs. V

LBIC
Spatially resolved IQE-measurement:
  • JSC& reflectance for 6 wavelengths simultaneously (532 nm ... 980 nm)
  • Spot diameter approx. 100 μm
  • Map with 1000 x 1000 pixels in approx. 3 h
  • Calibration based on global EQE / reflectance

EL
Electroluminescence imaging:
  • TE cooled 8.3 MPixel Si CCD camera
  • Motorized setting of distance and focus
  • Averaging and dark image subtraction
  • 3-step capture for RS-images (after D. Hinken)

LIT
Lock-In thermography:
  • MWIR camera with 320 x 256 Pixel or 640 x 512 Pixel
  • DLIT and ILIT (with LED-array, regulated intensity >1 sun, homogeneity +/-10%)
  • Motorized setting of distance and focus


Some advantages of having the most important techniques combined in one machine are:
  • Very short time to the results
  • Well defined conditions and degradation state of the solar cell
  • Mutual calibration of methods
  • High degree of automation