Dielectric and modulus analysis of the photoabsorber Cu2SnS3

Dielectric properties of the ternary semiconductor compound Cu2SnS3 is studied for the first time in the high temperature range from 300 °C to 440 °C with the frequency range 1 kHz to 1 MHz. The dielectric constant ε′ and dielectric loss tan(δ) were observed to increase with temperature and decrease rapidly with frequency to remains constant at high frequencies. The variation of the dielectric loss Ln(ε") with Ln(ω) was found to follow the empirical law, ε"=Bωm(T). The dielectric data were analyzed using complex electrical modulus M* at various temperatures. The activation energy responsible for the relaxation is estimated from the analysis of the modulus spectra. The value of the hopping barrier potential is estimated from the dielectric loss and compared with the value previously obtained from ac-conductivity. These results are critical for understanding the behavior of based polycrystalline family of Cu2SnS3 for absorber materials in solar-cells.