Lattice-dynamical and photoelastic properties of GaSe under high pressures studied by Raman scattering and electronic susceptibility

Kuroda, Noritaka; Ueno, Osamu; Nishina, Y.

doi:10.1103/physrevb.35.3860

Cited by 43 publications

(32 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The absorption at 1.84 THz was assigned to A 1 Ј-A 2 Љ͑LO͒͑60.1 cm −1 ͒, which was also observed in Raman measurements. 17,18 From the relationship of The fit to the measured absorption coefficient ␣͑ ͒ and the index of refraction n͑ ͒ is quite good over the entire frequency range, as is the fit to the real part of r ͑ ͒ ͓see Fig. 3͑a͔͒.…”

mentioning

confidence: 99%

Terahertz studies of the dielectric response and second-order phonons in a GaSe crystal

Zeng

Kartazayev

et al. 2005

Applied Physics Letters

View full text Add to dashboard Cite

The dielectric function and momentum relaxation time of carriers for a single-crystal GaSe were investigated using terahertz time-domain spectroscopy over the frequency range from 0.4to2.4THz. The key parameters determined from THz data using the Drude model are: the plasma frequency ωp=2.6±0.2THz, the average momentum relaxation time ⟨τ⟩=56±2fs, and the mobility μ=89cm2∕Vs for electrons. The THz absorption spectrum showed resonance structures attributed to the difference frequency combinations associated with acoustical and optical phonons.

show abstract

mentioning

confidence: 99%

Terahertz studies of the dielectric response and second-order phonons in a GaSe crystal

Zeng

Kartazayev

et al. 2005

Applied Physics Letters

View full text Add to dashboard Cite

show abstract

“…Several Raman scattering experiments under pressure have already been performed on GaSe [3−6]. The pressure dependence and the mode Grüneisen parameters for Raman-active phonons of ε-GaSe have been measured up to 1 GPa [3, 4], 3.5 GPa [5], and 8 GPa [6]. Recently [7,8] high-pressure X-ray powder diffraction studies have been made on ε-GaSe.…”

mentioning

confidence: 99%

Raman scattering under pressure and the phase transition in ε‐GaSe

Kulibekov

Olijnyk

Jephcoat

et al. 2003

Physica Status Solidi (b)

View full text Add to dashboard Cite

Raman scattering in ε-GaSe has been investigated at room temperature in a diamond anvil cell by using helium gas as a pressure transmitting medium. The first observation of the solid − solid phase transition under pressure from a hexagonal structure at ambient pressure to a NaCl-type at around 29.2 GPa is reported. A photoinduced change in the pressurised crystal was observed. The transition under pressure was found to be irreversible at room temperature. It was shown that the pressurised form of ε-GaSe at ambient conditions most probably belongs to the γ-type as characterised by an increased intensity of the Raman modes at 234 cm −1 and 250 cmGallium selenide is a layer semiconductor. Four distinct modifications, the β-, the ε-, the γ-and the δ-types were reported for GaSe, differing by the stacking order of the two-dimensional Se−Ga−Ga−Se sheet [1]. The differences between these types arise from the stacking of layers as well as from the number of layers per unit cell. The ε-modification (D 3h 1 space group (SG), containing two layers per unit cell) is the most common and best studied. Up to now the existence of the β-modification (D 6h 4 SG, two layers per unit cell) has not been confirmed. The γ-type has three layers (C 3v 5 SG), and the δ-type contains four layers per unit cell (C 6v 4 SG). Normally the crystals grown by the Bridgman method are a mixture of ε-and γ-types, with a predominant content of the former.Most common and well investigated among the different polytypes is ε-GaSe, which is one of the promising materials for far-infrared conversion applications [2]. The properties of ε-GaSe at ambient conditions (room temperature, atmospheric pressure) are reasonably well known. Several Raman scattering experiments under pressure have already been performed on GaSe [3−6]. The pressure dependence and the mode Grüneisen parameters for Raman-active phonons of ε-GaSe have been measured up to 1 GPa [3, 4], 3.5 GPa [5], and 8 GPa [6]. Recently [7,8] high-pressure X-ray powder diffraction studies have been made on ε-GaSe. It was shown that at pressures of 29 GPa [7] and of around 25 GPa [8] the crystal undergoes a phase transition (PT) to the NaCl-type structure. The reason for this discrepancy is

show abstract

“…4(a). Due to the D 1 3h space group that GaSe crystal belongs to, there are the following normal modes: 13) …”

Section: Raman Scatteringmentioning

confidence: 99%

“…The reason for this is that the lattice mismatch between the GaSe film and sapphire produced numerous stress in the initial growth procedure. The larger stresses () from the pressure effect on the GaSe films can reveal that 13) wðÞ ¼ wð0Þ þ @w @ where the wð0Þ (¼ 250:5 cm À1 ) is the E 0 (LO) mode frequency under zero pressure. These estimated results of stress are shown in Fig.…”

Section: Raman Scatteringmentioning

confidence: 99%

Fabrication and Optical Property of GaSe Thin Films Grown by Pulsed Laser Deposition

Lee

Hsu

et al. 2003

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

The highly oriented (001) GaSe film on c-cut sapphire (0001) was successfully fabricated by pulsed laser deposition. As growth temperature decreases from 550 C to 375 C, the structure of films changes from cubic zinc-blende Ga 2 Se 3 phase to GaSe phase. The growth temperature of the critical transition from Ga 2 Se 3 phase to GaSe phase is around 500 C. From atomic force microscope (AFM) results, it is observed that the growth process of GaSe film is in the manner of layer plus island growth. Besides, the optimal growth conditions of as-grown GaSe film were obtained at a substrate temperature of 400 C and laser energy density of 11.7 J/cm 2 . When the thickness of films goes beyond 800 # A, the stress will be released and the thickness of 1200 # A results in an optimal GaSe film. Furthermore, the indirect bound exciton emission and the recombination via impurity levels or structural defects were observed from low-temperature photoluminescence measurement.

show abstract

Lattice-dynamical and photoelastic properties of GaSe under high pressures studied by Raman scattering and electronic susceptibility

Cited by 43 publications

References 40 publications

Terahertz studies of the dielectric response and second-order phonons in a GaSe crystal

Terahertz studies of the dielectric response and second-order phonons in a GaSe crystal

Raman scattering under pressure and the phase transition in ε‐GaSe

Fabrication and Optical Property of GaSe Thin Films Grown by Pulsed Laser Deposition

Contact Info

Product

Resources

About