Fine structure of the exciton spectrum in GaSe

Thanh, Le Chi; Depeursinge, C.

doi:10.1016/0038-1098(78)90166-7

Cited by 9 publications

(1 citation statement)

References 16 publications

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“…Among these, the εand γ-phases are the most common and have a pseudodirect optical bandgap. In these phases, the indirect bandgap is only 25 meV lower than the direct bandgap [16].…”

Section: Introductionmentioning

confidence: 90%

The Wannier-Mott Exciton, Bound Exciton, and Optical Phonon Replicas of Single-Crystal GaSe

Le,

Huong,

Nguyen

et al. 2024

Crystals

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We report the absorption and photoluminescence spectra of GaSe single crystals in the near-edge region. The temperatures explored the range from 17 to 300 K. Specifically, at a temperature of 17 K, the photoluminescence spectrum reveals an interesting phenomenon: the Wannier-Mott exciton separates into two states. These states are a triplet state with an energy of 2.103 eV and a singlet state with an energy of 2.109 eV. The energy difference between these two states is 6 meV. Furthermore, the bound exciton (BX) can be localized at an energy of 2.093 eV. It is worth noting that its phonon replicas (BX-nLO) can be clearly distinguished up to the fourth order. Interestingly, the energy gaps between these replicas exhibit a consistent spacing of 7 ± 0.5 meV. This intriguing finding suggests a high-quality crystalline structure as well as a strong coupling between the phonon and BX-nLO. Additionally, at low temperatures, both the ground state (n = 1) at 2.11 eV and the excited state (n = 2) at 2.127 eV of free excitons can be observed.

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“…Among these, the εand γ-phases are the most common and have a pseudodirect optical bandgap. In these phases, the indirect bandgap is only 25 meV lower than the direct bandgap [16].…”

Section: Introductionmentioning

confidence: 90%