文章基本信息

标题：Optically decomposed near-band-edge structure and excitonic transitions in Ga₂S₃
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作者：Ching-Hwa Ho ; Hsin-Hung Chen
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2014
卷号：4
DOI：10.1038/srep06143
出版社：Springer Nature
摘要：The band-edge structure and band gap are key parameters for a functional chalcogenide semiconductor to its applications in optoelectronics, nanoelectronics, and photonics devices. Here, we firstly demonstrate the complete study of experimental band-edge structure and excitonic transitions of monoclinic digallium trisulfide (Ga₂S₃) using photoluminescence (PL), thermoreflectance (TR), and optical absorption measurements at low and room temperatures. According to the experimental results of optical measurements, three band-edge transitions of E_A = 3.052 eV, E_B = 3.240 eV, and E_C = 3.328 eV are respectively determined and they are proven to construct the main band-edge structure of Ga₂S₃. Distinctly optical-anisotropic behaviors by orientation- and polarization-dependent TR measurements are, respectively, relevant to distinguish the origins of the E_A, E_B, and E_C transitions. The results indicated that the three band-edge transitions are coming from different origins. Low-temperature PL results show defect emissions, bound-exciton and free-exciton luminescences in the radiation spectra of Ga₂S₃. The below-band-edge transitions are respectively characterized. On the basis of experimental analyses, the optical property of near-band-edge structure and excitonic transitions in the monoclinic Ga₂S₃ crystal is revealed.