Mapped at 40 sites/ minute. Full spectrum acquired at each site.
Light Biasing used to Study Triple Junction Cell, Inverted MM
Solid line: monochromator QE system (>10 min)
Dashed line: Tau Science FlashQE (4 sec)
Electroluminescence Image of Cell:
In UV (λ = 390nm), ~7% QE Enhancement is seen at the wafer edge. Absorption depth: 0.1 μm
Since FlashQE acquires spectra is real-time, it can be used for novel applications such as monitoring the evolution of spectral response during a temperature ramp. These are results from a 60 second measurement, warning the sample from 25-43C.
As Temp rises:Band Edge Redshift resolved: 1.2-1.8 meV/C
Wavelength Resolved QE temp coefficient
The
bandgap narrows (Varshni Equation) causing QE to increase near the
band gap:
The
overlayer (Nitride) absorption redshifts causing QE to decrease in
the UV
