III–VI Chalcogenide Semiconductor Crystals for Broadband Tunable THz Sources and Sensors

Mandal, Krishna C.; Kang, Sung Hoon; Choi, Michael K.; Chen, Jian; Zhang, Xicheng; Schleicher, James M.; Schmuttenmaer, Charles A.; Fernelius, Nils C.

doi:10.1109/jstqe.2007.912767

Cited by 42 publications

(26 citation statements)

References 20 publications

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“…These special structures can exhibit unique in-plane and out-of-plane optical and electrical properties [1][2][3], which apply to potential applications in the field of terahertz radiation emission [4,5], radiation detectors [6,7], and solar cells [8] in the past few years. Most III-VIA layered compounds, such as GaS, GaSe, InSe [9,10], have hexagonal structure with all M-M (M = Ga, In) bonds perpendicular to the layers, and the main symmetry axis parallel to M-M bonds.…”

Section: Introductionmentioning

confidence: 99%

Lattice Vibration of Layered GaTe Single Crystals

et al. 2018

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Abstract:The effect of interlayer interaction on in-layer structure of laminar GaTe crystals was studied according to the lattice vibration using micro-Raman analysis. The results were also confirmed by the first principle calculations. Accordingly, the relationship between lattice vibration and crystal structure was established. Ten peaks were observed in the micro-Raman spectra from 100 cm −1 to 300 cm −1 . Eight of them fit Raman-active vibration modes and the corresponding displacement vectors were calculated, which proved that the two modes situated at 128.7 cm −1 and 145.7 cm −1 were related to the lattice vibration of GaTe, instead of impurities or defects. Davydov splitting in GaTe was identified and confirmed by the existence of the other two modes, conjugate modes, at 110.7 cm −1 (∆ω = 33.1 cm −1 ) and 172.5 cm −1 (∆ω = 49.5 cm −1 ), indicates that the weak interlayer coupling has a significant effect on lattice vibrations in the two-layer monoclinic unit cell. Our results further proved the existence of two layers in each GaTe unit cell.

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Section: Introductionmentioning

confidence: 99%

Lattice Vibration of Layered GaTe Single Crystals

et al. 2018

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“…[1][2][3][4] GaSe is highly efficient as a broadband tunable source up to 40 THz and as a sensor up to 100 THz. 4,5 In short, GaSe (and related doped and un-doped III-VI semiconductors such as GaTe) have emerged as valuable systems in the very active THz research field. [1][2][3]5,6,[8][9][10][11] Work on GaTe and doped GaTe crystals includes the growth and characterization of these systems for broadband tunable THz sources and sensors.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3]5,6,[8][9][10][11] Work on GaTe and doped GaTe crystals includes the growth and characterization of these systems for broadband tunable THz sources and sensors. 5 Doping with Te, 3,5 S, Cr, 2,6 Ag, 1 and Er 7 was found to strengthen GaSe. Doping with In was found to significantly enhance the physical properties and strengthen the crystals enough to allow optical surfaces to be cut and polished along additional directions.…”

Section: Introductionmentioning

confidence: 99%

“…2, 3,5,6,[8][9][10][11] First-principles theoretical studies investigating the mechanical and electrical properties Te-based systems were also conducted. 3 Unlike doping with In, the incorporation of a transition metal element raises intriguing possibilities for coupling the magnetic properties of the transition metal ion with the host III-VI semiconductor leading to optical or electrical transport effects.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic properties of the layered III-VI diluted magnetic semiconductor Ga1−xFexTe

et al. 2016

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Magnetic properties of single crystalline Ga1−xFexTe (x = 0.05) have been measured. GaTe and related layered III-VI semiconductors exhibit a rich collection of important properties for THz generation and detection. The magnetization versus field for an x = 0.05 sample deviates from the linear response seen previously in Ga1−xMnxSe and Ga1−xMnxS and reaches a maximum of 0.68 emu/g at 2 K in 7 T. The magnetization of Ga1−xFexTe saturates rapidly even at room temperature where the magnetization reaches 50% of saturation in a field of only 0.2 T. In 0.1 T at temperatures between 50 and 400 K, the magnetization drops to a roughly constant 0.22 emu/g. In 0 T, the magnetization drops to zero with no hysteresis present. The data is consistent with Van-Vleck paramagnetism combined with a pronounced crystalline anisotropy, which is similar to that observed for Ga1−xFexSe. Neither the broad thermal hysteresis observed from 100-300 K in In1−xMnxSe nor the spin-glass behavior observed around 10.9 K in Ga1−xMnxS are observed in Ga1−xFexTe. Single crystal x-ray diffraction data yield a rhombohedral space group bearing hexagonal axes, namely R3c. The unit cell dimensions were a = 5.01 Å, b = 5.01 Å, and c = 17.02 Å, with α = 90°, β = 90°, and γ = 120° giving a unit cell volume of 369 Å3.

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“…Unfortunately, the extremely poor mechanical properties (almost zero hardness on the Mohs scale and easy cleavage) limit use of these layered crystals of symmetry point group 6 _ 2m to intralaboratory applications. Recently, with the aim of expanding nonlinear optics applications, the mechanical properties of GaSe crystals have been significantly improved as a result of doping with Group III and Group IV elements of Mendeleev's Periodic Table (Al [3], S [4], In [5-7], Te [8,9], Er [10]) and growing the corresponding crystals of the solid solutions, and also by growing crystals from GaSe:AgGaSe 2 [6] and GaSe:AgGaS 2 [11] melts. In contrast to GaSe crystals, AgGaSe 2 and AgGaS 2 crystals have symmetry point group 4 _ 2m.…”

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confidence: 99%

Dispersion properties of GaSe1-x S x in the terahertz range

Zhang

Guo

et al. 2011

J Appl Spectrosc

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We grew nonlinear crystals of the solid solutions GaSe 1-x S x (x ≤ 0.4) by the vertical Bridgman method. The increase in hardness from 8 kg/mm 2 for x = 0 to ~20 kg/mm 2 for x = 0.4 as a result of the presence of sulfur in the GaSe crystals allowed us to use a special technology to make working samples with position of the optic axis in the plane of the entrance surfaces, and for the first time to make direct measurements of the dispersion properties n e (λ) for the extraordinary wave and n o (λ) for the ordinary wave in the terahertz range of the spectrum by pulsed terahertz spectroscopy. We show that it is possible to realize an unconventional ee-e type of interaction in generation of terahertz radiation.Introduction. The unique set of physical properties in nonlinear GaSe crystals, responsible for the efficiency of parametric frequency conversion processes for converting radiation in the near IR and mid-IR ranges to the terahertz range of the spectrum [1, 2], has attracted steady attention from many researchers and developers. Unfortunately, the extremely poor mechanical properties (almost zero hardness on the Mohs scale and easy cleavage) limit use of these layered crystals of symmetry point group 6 _ 2m to intralaboratory applications. Recently, with the aim of expanding nonlinear optics applications, the mechanical properties of GaSe crystals have been significantly improved as a result of doping with Group III and Group IV elements of Mendeleev's Periodic Table (Al [3], S [4], In [5-7], Te [8,9], Er [10]) and growing the corresponding crystals of the solid solutions, and also by growing crystals from GaSe:AgGaSe 2 [6] and GaSe:AgGaS 2 [11] melts. In contrast to GaSe crystals, AgGaSe 2 and AgGaS 2 crystals have symmetry point group 4 _ 2m. It has been established that besides the mechanical properties, other key physical properties of GaSe crystals can be controllably modified by selection of the sulfur content. Introducing large concentrations of sulfur, indium, and tellurium (leading to a change in the lattice parameters) have the best possibilities in this regard; in other words, growing nonlinear crystals of solid solutions according to the chemical formulas GaSe:GaS → GaSe 1-x S x [4], [12][13][14][15][16][17][18][19], GaSe:InSe → Ga 1-x In x Se [5,7], and GaSe:GaTe → GaSe 1-x Te x [8,9]. Introducing small sulfur ions eliminates cleavage defects in the GaSe crystals and reduces linear optical losses in the region of maximum transparency (optimal doping level, 2-3 wt.%), and also increases the thermal conductivity severalfold orthogonal to the growth layers, as a result of substitution of selenium ions, filling vacancies, and intercalation in the interlayer space. As a result of these changes, the radiation resistance relative to nanosecond pump pulses increases by 20%-30%. The increase in the mixing ratio to x ≤ 0.4 shifts the short-wavelength edge of the transmission spec-

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III–VI Chalcogenide Semiconductor Crystals for Broadband Tunable THz Sources and Sensors

Cited by 42 publications

References 20 publications

Lattice Vibration of Layered GaTe Single Crystals

Lattice Vibration of Layered GaTe Single Crystals

Magnetic properties of the layered III-VI diluted magnetic semiconductor Ga1−xFexTe

Dispersion properties of GaSe1-x S x in the terahertz range

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