Method for measuring a semiconductor structure, which is a solar cell or a precursor of a solar cell

A method for measuring a semiconductor structure, which comprises an emitter and a base;

• wherein the semiconductor is a solar cell or a precursor of a solar cell, the method comprising the following steps:
• (A) creating luminescence radiation by a planar impingement of the semiconductor structure with an excitation radiation on the semiconductor structure and spatially resolved measurements of the luminescence radiation emitted by the semiconductor structure, with a first measurement being performed, via a camera, at a first measuring condition (a) and depending at least on the measurements yielded from the first measurement, generating a first spatially resolved, voltage-calibrated image Va(xi) for a multitude of spatial points xi of the solar cell from the measurements yielded in step A, and
• (B) using a processing unit to determine spatially resolved features of the semiconductor structure with regards to at least one of a spatially resolved dark saturation current j0(xi), a spatially resolved resistance of an emitter layer ρ(xi), or a spatially resolved local series resistance Rs(xi) for the multitude of spatial points xi dependent at least on the first voltage-calibrated image Va(xi) determined in step A,
• and additionally performing in step A, at least a second measurement at a second measurement condition (b) different from the first measurement condition (a) and, depending at least on the measurements yielded from the second measurement,
• generating a second spatially resolved, voltage calibrated image Vb(xi) for the multitude of spatial points xi from the measurements yielded in step A such that in step A in the two measurements
• the first and second measuring conditions (a and b) of the first and second measurements are different with regards to at least one of intensities, spectral compositions of the excitation radiation, or a predetermined external voltage Vext, by which the semiconductor structure is impinged via electric contacts, and
• additionally for each of the first and second measuring conditions and b) a voltage-independent, spatially independent short-circuit current density (jP,a, jP,b) of the current flowing under the respective measuring conditions with given short-circuit conditions is at least one of predetermined or measured, and
• in step B determination of the spatially resolved, electric features occurring at each of the spatial locations xi is dependent on at least the short-circuit current densities (jP,a, jP,b),
• and a voltage-dependent, spatially dependent dark current density (jD,a(xi), jP,b(xi)) for each measurement condition occurs, with the dark current densities (jD,a(xi), jP,b(xi)) at least being dependent on the voltage-independent dark saturation current density (j0,(xi)) and the two voltages (Va(xi), Vb(xi)) resulting from the respective voltage images for the location xi, without relying on given values for at least one of:
• dark saturation current density;
• the resistance of the emitter layer;
• or the series resistance as external input.