Temperature dependence of free-exciton photoluminescence in crystalline GaTe

Wan, Jian Wei; Brebner, J. L.; Leonelli, R.; Zhao, Guoxiang; Graham, Joseph

doi:10.1103/physrevb.48.5197

Cited by 48 publications

(33 citation statements)

References 29 publications

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“…The longitudinal optical ͑LO͒ phonons in GaTe, determined by Wan et al 10 from PL measurements up to 40 K of the full width at half maximum of the free exciton peak, have an energy of 14 meV, which agrees with the value obtained in the above fit. Moreover, this value is the same as the energy proposed by Camassel et al in Ref.…”

Section: A Free Exciton Luminescencesupporting

confidence: 85%

“…Two types of free exciton recombination at 1.779 (nϭ1) and 1.791 eV (nϭ2) were clearly visible and the Rydberg energy was found to be 16 meV. Other authors [9][10][11][12][13][14] have studied the structure of free excitonic recombination in photoluminescence ͑PL͒ experiments. However, very little work has been done on optical recombination apart from that due to free excitons.…”

Section: Introductionmentioning

confidence: 98%

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Recombination processes in unintentionally doped GaTe single crystals

Zubiaga

Garcı́a

Plazaola

et al. 2002

Journal of Applied Physics

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Emission spectra of GaTe single crystals in the range of 1.90-1.38 eV have been analyzed at different temperatures and excitation intensities by photoluminescence, photoluminescence excitation, and selective photoluminescence. A decrease in band gap energy with an increase in temperature was obtained from the redshift of the free exciton recombination peak. The energy of longitudinal optical phonons was found to be 14Ϯ1 meV. A value of 1.796Ϯ0.001 eV for the band gap at 10 K was determined, and the bound exciton energy was found to be 18Ϯ0.3 meV. The activation energy of the thermal quenching of the main recombination peaks and of the ones relating to the ionization energy of impurities and defects was analyzed. The results obtained show the existence of two acceptor levels with ionization energies of 110Ϯ5 and 150Ϯ5 meV, respectively, and one donor level with an ionization energy of 75Ϯ5 meV. The study of chemical composition by inductively coupled plasma-optical emission spectroscopy and x-ray energy dispersion spectroscopy shows the existence of Na, Li, and Si. Sodium and lithium impurities could be associated with acceptor levels at gallium substitutional sites, and silicon ones with a donor level at Ga sites, whose vacancies can also be involved in these electronic levels.

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Section: A Free Exciton Luminescencesupporting

confidence: 85%

Section: Introductionmentioning

confidence: 98%

Recombination processes in unintentionally doped GaTe single crystals

Zubiaga

Garcı́a

Plazaola

et al. 2002

Journal of Applied Physics

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“…[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: 94%

“…Free-exciton, boundexciton, and edge emissions of undoped GaTe crystal have been well investigated, [7][8][9][10][11][12] and a shallow acceptor level around 0.15 eV has been reported and identified to be gallium vacancy V Ga . Undoped GaTe Schottky diodes were fabricated and tested, [3][4][5][6] and one DLTS measurement conducted at room temperature and above was reported.…”

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

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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.

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“…GaTe is a relatively known semiconductor compound [21][22][23][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]45,47] and exist successful but limited Schottky contact studies [21][22][23][37][38][39][40] made using GaTe. GaTe belongs to the III-VI group in the periodic table and has a layered nature.…”

Section: Introductionmentioning

confidence: 99%