Exciton transitions from spin-orbit split off valence bands in layer compound InSe

Kuroda, Noritaka; Munakata, Ichiro; Nishina, Y.

doi:10.1016/0038-1098(80)90753-x

Cited by 67 publications

(38 citation statements)

References 20 publications

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“…9 give rise to the two observed intense transitions in InSe and GaSe and the other two are not observed due to the low value of the matrix element. This discussion is coherent with previous assignments of the energy difference between these transitions to the spin −orbit interaction, based in its insensitivity to pressure [6] or in an extension of the Hopfield's quasi-cubic model [26,27].…”

Section: Spin−orbit Splitting Of Z 3 Valence Bandssupporting

confidence: 88%

“…The absorption spectra of InSe and GaSe exhibit only two transitions at 1.15 and 1.5 eV above the fundamental one [6,26]. This contrasts with the fact that there are two pairs of valence bands with Se p x −p y character (belonging to the Z 3 representation), that would split in four nondegenerate bands due to spin −orbit interaction.…”

Section: Spin−orbit Splitting Of Z 3 Valence Bandsmentioning

confidence: 88%

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Specific features of the electronic structure of III–VI layered semiconductors: recent results on structural and optical measurements under pressure and electronic structure calculations

Segura

Manjón

Errandonea

et al. 2003

Physica Status Solidi (b)

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In this paper we review some recent results on the electronic structure of III − VI layered semiconductors and its dependence under pressure, stressing the specific features that differentiate their behaviour from that of tetrahedrally coordinated semiconductors. We will focus on several unexpected results that have led to changes in the image that was currently accepted a few years ago. Intralayer bond angles change under pressure and the layer "thickness" remains virtually constant or increases. As a consequence, models based in intra-and inter-layer deformation potentials fail in explaining the low pressure nonlinearity of the band gap. Numerical-atomic-orbital/density-functional-theory electronic structure calculations allow for an interpretation of the evolution of the absorption edge under pressure. In particular, they show how the structure of the non-degenerated valence band maximum in InSe becomes more complex under pressure leading to a non-conventional direct-to-indirect crossover. The valence band maximum in InSe above 4 GPa exhibits a quite singular feature: a "ring-shaped" constant energy surface and, consequently, a density of states depending on energy as in 2D electronic systems.

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Section: Spin−orbit Splitting Of Z 3 Valence Bandssupporting

confidence: 88%

Section: Spin−orbit Splitting Of Z 3 Valence Bandsmentioning

confidence: 88%

Specific features of the electronic structure of III–VI layered semiconductors: recent results on structural and optical measurements under pressure and electronic structure calculations

Segura

Manjón

Errandonea

et al. 2003

Physica Status Solidi (b)

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“…The other two bands known as E = 1 (C-band) and E 1 (A-band) arise from the S-like to P y -and P x -like symmetries. The authors determined the value of A-band energy as 2.75 eV [14,15] which is the same as that we have observed in this work. The C-band which was not reported by Segura et al is calculated from the E-axis crossing of the (aE) 2 -E variation as described above.…”

supporting

confidence: 83%

Optical characterization of the MgO/InSe interface

Kayed

Qasrawi

Elsayed

2014

Physica Status Solidi (b)

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In this work, a 500 nm thick MgO layer deposited on the physically evaporated amorphous InSe thin film substrate is designed as a window for the MgO/InSe terahertz resonators. The optical properties including the reflectance and the dielectric constant dependence on the angle of incidence (u i ), the normal transmittance, and the absorption coefficient of the interface were investigated in the range of $270-1000 THz. It was observed that the total reflectivity of the substrate continuously decreases with increasing u i in the range of 33-808. The spectra of InSe and MgO/InSe revealed strong dielectric resonance patterns below 450 THz. The energy bands of the direct allowed transitions in InSe film shrunk from 3.90, 2.75, and 1.49 eV to 3.71, 2.10, and 0.96 eV when MgO was deposited onto the InSe film. By analyzing the dielectric spectra, we were able to determine the static and lattice dielectric constants in addition to the oscillator and dispersion energies. The latter energy increased from 27.43 to 35.84 via interface construction.

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“…The binding energy of A peak is estimated to be 16.4 meV, which is close to the previously reported value of exciton binding energy in bulk InSe (14.5 meV). [30][31][32][33] Arrhenius fitting of the peak D1 and D2 results in the defect binding energy of 35.3 meV (D1) and 25.6 meV (D2), respectively. The larger binding energy from the defects results in the red shift of the D1 and D2 peak compared with that of the A peak.…”

Section: Main Textmentioning

confidence: 99%

Enhanced Light Emission from the Ridge of Two-Dimensional InSe Flakes

Wang

et al. 2018

Nano Lett.

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InSe, a newly rediscovered two-dimensional (2D) semiconductor, possesses superior electrical and optical properties as a direct-band-gap semiconductor with high mobility from bulk to atomically thin layers and is drastically different from transition-metal dichalcogenides, in which the direct band gap only exists at the single-layer limit. However, absorption in InSe is mostly dominated by an out-of-plane dipole contribution, which results in the limited absorption of normally incident light that can only excite the in-plane dipole at resonance. To address this challenge, we have explored a unique geometric ridge state of the 2D flake without compromising the sample quality. We observed the enhanced absorption at the ridge over a broad range of excitation frequencies from photocurrent and photoluminescence (PL) measurements. In addition, we have discovered new PL peaks at low temperatures due to defect states on the ridge, which can be as much as ∼60 times stronger than the intrinsic PL peak of InSe. Interestingly, the PL of the defects is highly tunable through an external electrical field, which can be attributed to the Stark effect of the localized defects. InSe ridges thus provide new avenues for manipulating light-matter interactions and defect engineering that are vitally crucial for novel optoelectronic devices based on 2D semiconductors.

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Exciton transitions from spin-orbit split off valence bands in layer compound InSe

Cited by 67 publications

References 20 publications

Specific features of the electronic structure of III–VI layered semiconductors: recent results on structural and optical measurements under pressure and electronic structure calculations

Specific features of the electronic structure of III–VI layered semiconductors: recent results on structural and optical measurements under pressure and electronic structure calculations

Optical characterization of the MgO/InSe interface

Enhanced Light Emission from the Ridge of Two-Dimensional InSe Flakes

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