Some Optical Properties of Layer-Type Semiconductor GaTe

Tatsuyama, C.; Watanabe, Yasuharu; Hamaguchi, Chihiro; Nakai, Junkichi

doi:10.1143/jpsj.29.150

Cited by 62 publications

(31 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The intralayer bonding of PTMCs has strong covalent character, while the interlayer interaction has weak vdW character. Bulk GaSe crystal was reported to be a direct-gap semiconductor with a band gap of 2.0 eV, while bulk GaS was found to be an indirect-gap semiconductor with a band gap of 2.4 eV [12,13]. In recent years large area ultrathin layers of GaS and GaSe crystals were successfully synthesized on SiO 2 /Si substrates by using micromechanical cleavage technique [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Mechanical properties of monolayer GaS and GaSe crystals

et al. 2016

View full text Add to dashboard Cite

The mechanical properties of monolayer GaS and GaSe crystals are investigated in terms of their elastic constants: in-plane stiffness (C), Poisson ratio (ν), and ultimate strength (σ U ) by means of first-principles calculations. The calculated elastic constants are compared with those of graphene and monolayer MoS 2 . Our results indicate that monolayer GaS is a stiffer material than monolayer GaSe crystals due to the more ionic character of the Ga-S bonds than the Ga-Se bonds. Although their Poisson ratio values are very close to each other, 0.26 and 0.25 for GaS and GaSe, respectively, monolayer GaS is a stronger material than monolayer GaSe due to its slightly higher σ U value. However, GaS and GaSe crystals are found to be more ductile and flexible materials than graphene and MoS 2 . We have also analyzed the band-gap response of GaS and GaSe monolayers to biaxial tensile strain and predicted a semiconductor-metal crossover after 17% and 14% applied strain, respectively, for monolayer GaS and GaSe. In addition, we investigated how the mechanical properties are affected by charging. We found that the flexibility of single layer GaS and GaSe displays a sharp increase under 0.1e/cell charging due to the repulsive interactions between extra charges located on chalcogen atoms. These charging-controllable mechanical properties of single layers of GaS and GaSe can be of potential use for electromechanical applications.

show abstract

Section: Introductionmentioning

confidence: 99%

Mechanical properties of monolayer GaS and GaSe crystals

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Several groups, however, have reported that as-grown material appears always to be p-type, with high free carrier concentrations (∼10 16 -10 17 cm −3 ), low resistivities (∼20-200 Ω-cm), and very low carrier mobilities (∼10-60 cm 2 /V-s). [4][5][6][7][8][9] In the report, we describe the use of a fully ab-initio theoretical tool set [10][11][12] to analyze how intrinsic defects and accidental impurities hinder the performance of GaTe as a roomtemperature radiation detector, and how possible compensation dopants behave to improve the properties. In Sect.…”

Section: Introductionmentioning

confidence: 99%

Ab initioguided optimization of GaTe for radiation detection applications

Leão

Lordi

2011

Phys. Rev. B

View full text Add to dashboard Cite

The development of semiconductor-based radiation detectors that display high energy resolution while operating at room temperature is a pressing need for both scientific applications as well as homeland security. Practice has proven that the real performance of materials in such applications is often hindered by intrinsic defects and accidental impurities. Experimental efforts to improve the properties of such materials are both time consuming and costly, since they rely largely on trial and error. In this paper, the properties of gallium telluride (GaTe)-a high Z, moderate band gap semiconductor-are investigated for room-temperature radiation detection applications. Systematic theoretical modeling based on density functional theory calculations is used to suggest experimental processes to grow this semiconductor with optimal properties, by judiciously identifying the most detrimental native defects and devising ways to minimize their occurrence as well as compensating their electronic impact on the crystal. The analysis suggests that material grown Ga-rich would have significantly higher resistivity, carrier mobilities, and carrier lifetimes compared to Te-rich material. In addition, Ge doping and In doping can be effective for carrier compensation of the material. Doping with Ge can be especially effective, if the ambipolar nature of substitutional incorporation on both Ga and Te sites is exploited.

show abstract

“…[1][2][3][4][5][6][7][8][9][10][11][12] The band-gap energy of GaTe at room temperature is around 1.7 eV. This value is ideal for room-temperature x-ray and gamma-ray radiation detector applications.…”

Section: Introductionmentioning

confidence: 99%

“…Undoped GaTe is p-type with low resistivity ͑20 ⍀ ·cm͒ and low mobility ͑15 cm 2 / V·s͒. 2 To meet radiation detector application requirements ͑resistivityϾ 1 ϫ 10 9 ⍀ · cm, mobilityϳ 1 ϫ 10 3 cm 2 / V·s͒, the material should possess deep levels near the middle of the band gap, 13 and dopants have to be introduced into the material to compensate the native shallow acceptors. The type and intensity of both intrinsic and extrinsic defects have influence on the fundamental properties of GaTe; it is important to study defect levels between the valence and the conduction bands of GaTe crystals.…”

Section: Introductionmentioning

confidence: 99%

Deep levels in GaTe and GaTe:In crystals investigated by deep-level transient spectroscopy and photoluminescence

Cui

Caudel

Bhattacharya

et al. 2009

Journal of Applied Physics

View full text Add to dashboard Cite

Deep levels of undoped GaTe and indium-doped GaTe crystals are reported for samples grown by the vertical Bridgman technique. Schottky diodes of GaTe and GaTe:In have been fabricated and characterized using current-voltage, capacitance-voltage, and deep-level transient spectroscopy ͑DLTS͒. Three deep levels at 0.40, 0.59, and 0.67 eV above the valence band were found in undoped GaTe crystals. The level at 0.40 eV is associated with the complex consisting of gallium vacancy and gallium interstitial ͑V Ga -Ga i ͒, the level at 0.59 eV is identified as the tellurium-on-gallium antisite ͑Te Ga ͒, and the last one is tentatively assigned to be the doubly ionized gallium vacancy ͑V Ga ‫ء‬ ͒. Indium isoelectronic doping is found to have noticeable impacts on reducing the Schottky saturation current and suppressing the densities of Te Ga and V Ga ‫ء‬ defects. The peak which dominated the DLTS spectrum of GaTe:In is assigned to be the defect complex consisting of V Ga and indium interstitial ͑In i ͒. Low-temperature photoluminescence ͑PL͒ spectroscopy measurements were performed on GaTe and GaTe:In crystals. A shallow acceptor level at 140 meV corresponding to V Ga was measured in undoped GaTe. Two shallow acceptor levels at 123 and 74 meV corresponding to V Ga and indium-on-gallium antisite In Ga were observed in GaTe:In samples. The PL results suggested that the indium atoms could occupy gallium vacant sites during GaTe crystal growth period and thereby change the electrical and optical properties of GaTe crystal.

show abstract

Some Optical Properties of Layer-Type Semiconductor GaTe

Cited by 62 publications

References 10 publications

Mechanical properties of monolayer GaS and GaSe crystals

Mechanical properties of monolayer GaS and GaSe crystals

Ab initioguided optimization of GaTe for radiation detection applications

Deep levels in GaTe and GaTe:In crystals investigated by deep-level transient spectroscopy and photoluminescence

Contact Info

Product

Resources

About