The forbidden energy gap between the valence band (VB) and the conduction band (CB) of a material, which needs to be overcome to produce free charge carriers.
The bandgap determination is accomplished using the Tauc plots, where (αhν)n is plotted as a function of the energy hν (h- Planck’s constant, ν- energy frequency) for a given point in the library.
The power n is established based on the type of bandgap the material has. For a direct bandgap n=2 and for an indirect bandgap n=0.5. The obtained graph, from the (αhν)n vs. hν plot, contains a linear area to which a straight line is fitted and extrapolated to the energy (x) axis.
The point where the linear fit and the x-axis intercept is the bandgap of the material,
Over 100,000 band gaps were calculated from optical scans and thickness measurements for over 600 libraries.
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This method is used to obtain the optical properties of the material and device libraries.
The EDS detector in a high-resolution scanning electron microscope (HRSEM) was used to determine the compositions
The XRD is utilized to determine the crystalline structure and oxidation states of the different metal oxide layers we obtained.
In the J-V method the photocurrent is measured as a function of the photovoltage of the solar cell.
Sheet Resistance (SHR) is the resistance of a two-dimensional layer, for example thin film, doped semiconductor region.