Synthesis and characterization of Cu2ZnSnS4 bulk polycrystalline

Cu2ZnSnS4 bulk polycrystalline were synthesized by pressureless sintering (PLS) method in vacuum and spark plasma sintering (SPS) method. It was confirmed that there were no the secondary phases in a sample sintered by SPS method at 750 °C from the results of powder X-ray diffraction (XRD) patterns and Rietveld refinement. The Raman spectrum of the sample showed the strongest peak at 338 cm−1 with a shoulder at 350–370 cm−1, and the weaker peaks at about 255 and 289 cm−1, which originated from Cu2ZnSnS4. The FWHM of the strongest peak of 7.4 cm−1 was narrower than other samples. The photoluminescence (PL) spectrum measured at 15 K were observed a broad emission band with the maximum at 1.26 eV. Also, the measured photoluminescence excitation (PLE) for the band-edge emission was originated the energy transfer from the band-to-band excitation.The obtained activation energy was 62 ± 9 meV.