Lattice vibrations of pure and doped GaSe

Allakhverdiev, K. R.; Baykara, T.; Ellialtıoğlu, Şinasi; Hashimzade, F. M.; Huseinova, D. A.; Kawamura, Kee-YounJang; Kaya, A. A.; Kulibekov, A. M.; Onari, Seiichiro

doi:10.1016/j.materresbull.2005.10.015

Cited by 55 publications

(26 citation statements)

References 41 publications

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“…Gruneisen parameters intense Raman lines in the range above 100 cm -I, which are identical with those reported in [11] for all GaSe single crystals. This clearly indicates that actual lines are due to different intralayer bonding in GaSe crystals.…”

Section: Kinetics Of Synthesissupporting

confidence: 87%

“…This result is in conformity with the XRD result and confirms the e-modification of specimen. As far as the observation of only three sharp and intense Raman lines in the present work unlike 4-7 in single crystal cases [11], it is attributed to the fact that the powder form of synthesized material contains small-sized crystals, while data reported in [11] refer to bulk single crystalline materials. Some relevant information related to three Raman lines is provided in Table 1.…”

Section: Kinetics Of Synthesiscontrasting

confidence: 45%

“…Raman study Figure 3 shows the Raman spectra of synthesized polycrystalline gallium selenide (GaSe) powder within the Table 2 in [11]). From [11], it is clear that there are 4--7 Raman lines in the frequency range above 100 cm-I and 2-5 below 100 cm-I .…”

Section: Kinetics Of Synthesismentioning

confidence: 99%

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Controlled synthesis and structural characterization of polycrystalline GaSe

2010

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A comprehensive study on the synthesis and characterization of gallium selenide (GaSe) has been reported in this paper. Synthesis of gallium selenide (GaSe) from component elements has been carried out in a specially designed and fabricated quartz ampoule, with the help of a rocking furnace. X-ray diffractometry study revealed crystalline GaSe samples belonging to hexagonal system. Raman spectral study emphasized three sharp lines at 208.89, 253.95, and 306.52 cm-I, in good agreement with X-ray diffraction results. Scanning electron microscopy revealed particles of rock like structure, sized in the range 0.4-6 /lm.

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Section: Kinetics Of Synthesissupporting

confidence: 87%

Section: Kinetics Of Synthesiscontrasting

confidence: 45%

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Controlled synthesis and structural characterization of polycrystalline GaSe

2010

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“…This peak is attributed to defect levels resulting from impurities also 76 , again confirming Er incorporation. Very similar optical properties to that for Al-and Er-doped crystals were observed for GaSe doped with not isovalent Ag, which does not form binary isostructural compounds.…”

Section: Mid-ir Properties Of Al- Er- and Ag-doped Crystalsmentioning

confidence: 59%

“…Nevertheless, the transformation of the profiles of the short wave (exciton) (Figure 9) and the Raman (at 213 cm 21 , Figure 10) peaks confirm the increasing incorporation of Al with its increased concentration in the charge. The transformation of the Raman peak, at 213 cm 21 with increasing Al content (Figure 10 inset) is classified as being related to the impurity levels 76 .…”

Section: Mid-ir Properties Of Al- Er- and Ag-doped Crystalsmentioning

confidence: 99%

Doped GaSe crystals for laser frequency conversion

Guo

Xie

et al. 2015

Light Sci Appl

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In this review, we introduce the current state of the art of the growth technology of pure, lightly doped, and heavily doped (solid solution) nonlinear gallium selenide (GaSe) crystals that are able to generate broadband emission from the near infrared (IR) (0.8 mm) through the mid-and far-IR (terahertz (THz)) ranges and further into the millimeter wave (5.64 mm) range. For the first time, we show that appropriate doping is an efficient method controlling a range of the physical properties of GaSe crystals that are responsible for frequency conversion efficiency and exploitation parameters. After appropriate doping, uniform crystals grown by a modified technology with heat field rotation possess up to 3 times lower absorption coefficient in the main transparency window and THz range. Moreover, doping provides the following benefits: raises by up to 5 times the optical damage threshold; almost eliminates two-photon absorption; allows for dispersion control in the THz range independent of the mid-IR dispersion; and enables crystal processing in arbitrary directions due to the strengthened lattice. Finally, doped GaSe demonstrated better usefulness for processing compared with GaSe grown by the conventional technology and up to 15 times higher frequency conversion efficiency. INTRODUCTIONThe e-polytype of gallium selenide (hereinafter GaSe) has been known since 1934 1 and promises efficient optical frequency conversion and detection over a large range of wavelengths. The performance potential of GaSe, which belongs to the point group symmetry 6m2, can be attributed to its extreme physical properties. GaSe has a broadband transparency window over the range of 0.62-20 mm for non-polarized light continues at wavelengths o50 mm 2,3 . Other attractive physical properties of GaSe are its prodigious birefringence B 5 0.375 at l 5 10.6 mm and 0.79 at terahertz (THz) range 4 , and very high second-order nonlinear susceptibility d 22 5 54 pm V 21 at 10 mm 5 and 24.3 pm/V in the THz band 6 . Among the mid-infrared (IR) anisotropic nonlinear crystals, GaSe has the second highest optical damage threshold 7,8 and thermal conductivity in the plane of the (0001) A GaSe crystal was first used for laser frequency conversion in the mid-IR in 1972 9,10 . In subsequent years, GaSe was widely used for inlab mid-IR applications 5 . Over the past two decades, GaSe has been among the most promising nonlinear optical crystals for efficient generation of ultrabroadband radiation 0.8-5640 mm (with the

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Solution‐Processed GaSe Nanoflake‐Based Films for Photoelectrochemical Water Splitting and Photoelectrochemical‐Type Photodetectors

Zappia

Bianca

Bellani

et al. 2020

Adv Funct Materials

103

106

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Gallium selenide (GaSe) is a layered compound, which has been exploited in nonlinear optical applications and photodetectors due to its anisotropic structure and pseudodirect optical gap. Theoretical studies predict that its 2D form is a potential photocatalyst for water splitting reactions. Herein, the photoelectrochemical (PEC) characterization of GaSe nanoflakes (single‐/few‐layer flakes), produced via liquid phase exfoliation, for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in both acidic and alkaline media is reported. In 0.5 m H2SO4, the GaSe photoelectrodes display the best PEC performance, corresponding to a ratiometric power‐saved metric for HER (Φsaved,HER) of 0.09% and a ratiometric power‐saved metric for OER (Φsaved,OER) of 0.25%. When used as PEC‐type photodetectors, GaSe photoelectrodes show a responsivity of ≈0.16 A W−1 upon 455 nm illumination at a light intensity of 63.5 µW cm−2 and applied potential of −0.3 V versus reversible hydrogen electrode (RHE). Stability tests of GaSe photodetectors demonstrated a durable operation over tens of cathodic linear sweep voltammetry scans in 0.5 m H2SO4 for HER. In contrast, degradation of photoelectrodes occurred in both alkaline and anodic operation due to the highly oxidizing environment and O2‐induced (photo)oxidation effects. The results provide new insight into the PEC properties of GaSe nanoflakes for their exploitation in photoelectrocatalysis, PEC‐type photodetectors, and (bio)sensors.

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Lattice vibrations of pure and doped GaSe

Cited by 55 publications

References 41 publications

Controlled synthesis and structural characterization of polycrystalline GaSe

Controlled synthesis and structural characterization of polycrystalline GaSe

Doped GaSe crystals for laser frequency conversion

Solution‐Processed GaSe Nanoflake‐Based Films for Photoelectrochemical Water Splitting and Photoelectrochemical‐Type Photodetectors

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