Selective detection of secondary phases in Cu2ZnSn(S, Se)4 based absorbers by pre-resonant Raman spectroscopy

As the interest in Cu2ZnSn(S, Se)4 (CZTSSe) kesterite based solar cells increases, the development of new processes and characterization methodologies are required to satisfy the peculiarities of these emerging and complex materials. In this case, the formation of secondary phases is largely expected affecting the properties of the devices. In this report, we present a highly selective methodology to detect the most probable secondary phases in the CZTSSe system, based in the application of pre-resonant Raman concepts, by choosing the excitation wavelength best suited for each particular case.