Optical properties and electronic structures of CuSbS₂, CuSbSe₂, and CuSb(S_1−xSe_x)₂ solid solution

Abstract

To clarify electronic structures of CuSbS2, CuSbSe2, and CuSb(S1−xSex)2 solid solutions, these powder samples were synthesized by a mechanochemical process and post‐heating. CuSbS2 and CuSbSe2 have indirect and direct band gaps, of which the direct band gaps are a little wider than the indirect band gaps. The ionization energies of CuSb(S1−xSex)2 (0.0 ≤ x ≤ 1.0) powders were measured by photoemission yield spectroscopy (PYS). Energy levels of the valence band maximum (VBM) of the CuSb(S1−xSex)2 samples were estimated from the ionization energies. The electron affinity, energy level of conduction band minimum (CBM), of the CuSb(S1−xSex)2 samples could also be determined by adding the value of the optical band gap to the energy level of the VBM. The energy level of the VBM of the CuSb(S1−xSex)2 system monotonically increases from −5.45 eV for CuSbS2 (x = 0.0) to −5.15 eV for CuSbSe2 (x = 1.0). On the other hand, the energy levels of the indirect CBM of the CuSb(S1−xSex)2 system slightly decrease from −4.05 eV for CuSbS2 to −4.11 eV for CuSbSe2. The energy levels of the direct CBM also slightly decrease from −4.00 eV for CuSbS2 to −4.07 eV for CuSbSe2. We show the band alignment of CuSbS2 (CuSbSe2)‐based solar cells with a standard device structure of ZnO/CdS/CuSbS2 (CuSbSe2) absorber.

Excellent Thermoelectric Performance of 2D CuMN2 (M = Sb, Bi; N = S, Se) at Room Temperature

“…As shown in Figure S3 , SOC has a non-ignorable impact on band structure, especially for CuBiS 2 and CuBiSe 2 , so SOC was all considered in following calculations. As shown in Figure 3 , all the monolayers are narrow band-gap semiconductors with band gaps of 0.57~1.10 eV, which are slightly smaller than or comparable to their bulk structures [ 21 , 23 , 45 , 46 ]. Since the valence band maximum (VBM) and conduction band minimum (CBM) are both located at Γ point, both CuSbS 2 , CuSbSe 2 , and CuBiS 2 belong to direct bandgap semiconductors.…”

Cu-Doped Sb2Se3 Thin-Film Solar Cells Based on Hybrid Pulsed Electron Deposition/Radio Frequency Magnetron Sputtering Growth Techniques

“…This observation could be attributed to a potential barrier that Cu ions create for photocarrier extraction at either the FTO/Cu:Sb 2 Se 3 or Cu:Sb 2 Se 3 /CdS interfaces. In the former case, Cu ions may raise the minimum conduction band energy (since the minimum conduction band of CuSbSe 2 is at −4.07 eV [34]), thereby enhancing the band offset with FTO and impeding the extraction of photogenerated charge carriers. Alternatively, the non-perpendicular orientation of [Sb4Se6]n ribbons within the PED-grown 5%Cu:Sb 2 Se 3 layer could hinder photocarrier conduction.…”