Excitonic and electronic transitions in Me–Sb2Se3 structures

Beilstein Journal of Nanotechnology

Nicolae N. Syrbu¹  Victor V. Zalamai²  Ivan G. Stamov³  Stepan I. Beril³ 

[1] Laboratory of Micro-Optoelectronics, Technical University of Moldova, 168 Stefan cel Mare Avenue, 2004 Chisinau, Republic of Moldova;National Center for Materials Study and Testing, Technical University of Moldova, Bv. Stefan cel Mare 168, Chisinau 2004, Republic of Moldova;T.G. Shevchenko State University of Pridnestrovie, 25 Oktyabrya street 107, 3300 Tiraspol, Republic of Moldova;

关键词: anisotropy;    antimony triselenide;    band structure;    excitons;    optical spectroscopy;    reflection and absorption spectra;   

DOI  :  10.3762/bjnano.11.89

来源: DOAJ

【 摘 要 】

The optical anisotropy of the Sb2Se3 crystals was investigated at 300 and 11 K. Excitonic features of four excitons (A, B, C, and D) were observed in the optical spectra of the Sb2Se3 single crystals and in the photoelectric spectra of the Me–Sb2Se3 structures. The exciton parameters, such as the ground (n = 1) and excited (n = 2) state positions and the binding energy (Ry), were determined. The effective mass of the electrons at the bottom of the conduction band (mc* = 0.67m0) as well as the holes at the four top valence bands (mv1* = 3.32m0, mv2* = 3.83m0, mv3* = 3.23m0 and mv4* = 3.23m0) were calculated in the Г-point of the Brillouin zone. The magnitude of the valence band splitting V1–V2 due to the spin–orbit interaction (Δso = 35 meV) and the crystal field (Δcf = 13 meV) were estimated in the Brillouin zone center. The energy splitting between the bands V3–V4 was 191 meV. The identified features were discussed based on both the theoretically calculated energy band structure and the excitonic band symmetry in the Brillouin zone (k = 0) for crystals with an orthorhombic symmetry (Рnma). The photoelectric properties of the Me–Sb2S3 structures were investigated in the spectral range 1–1.8 eV under E||c and E⟂c polarization conditions and at different applied voltages.

【 授权许可】

Unknown