Photoreflectance study of ion beam synthesized β-FeSi2

Birdwell, A. Glen; Collins, S.; Glosser, R.; Leong, D.; Homewood, K. P.

doi:10.1063/1.1428792

Cited by 7 publications

(7 citation statements)

References 29 publications

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“…Lefki et al [36] and Yang et al [49] both have obtained a direct band gap of 0.85 eV from the experimental analysis which agrees quite well to that (0.84 eV) observed by Wang et al [3]. Birdwell et al [51] obtained a direct energy gap of E g = 0.806 eV for ␤-FeSi 2 by PL at 5 K and then calculated the energy band gap of ␤-FeSi 2 at 300 K to be 0.811 eV after adjusting for temperature and acceptor level. On the other hand, the direct band gap value of the ␤-FeSi 2 obtained by photo-luminescence is reported to be 0.81 eV at room temperature by most of the authors which matches quite closely with the bandgap value (0.87 eV) of our ␤-FeSi 2 sample determined by PL.…”

Section: 5supporting

confidence: 86%

“…Although most of the optical experimental observation conducted by Bost et al [48] and other authors [1,[49][50][51][52] showed that ␤-FeSi 2 is a direct band gap semiconductor with E g = 0.85-0.87 eV the papers related to band structure calculated by several authors [1,6,7,31,32] showed that it is both direct band gap semiconductor at Y and point as well as indirect band gap semiconductor along to Y along high symmetry directions. According to Filonov et al [1] and Eisebitt et al [34] the most important feature of the band structure is characterized by a direct band gap at point lies in between and Z k points which is 0.742 eV and 0.78 eV, respectively, whereas according to Christensen et al [32] and Eppenga et al [31] the calculated direct gap value at is about 0.80 eV and 0.92 eV, respectively.…”

Section: 5mentioning

confidence: 95%

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Synthesis and characterization of β-phase iron silicide nano-particles by chemical reduction

Sen

Gogurla

Banerji

et al. 2015

Materials Science and Engineering: B

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Section: 5supporting

confidence: 86%

Section: 5mentioning

confidence: 95%

Synthesis and characterization of β-phase iron silicide nano-particles by chemical reduction

Sen

Gogurla

Banerji

et al. 2015

Materials Science and Engineering: B

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“…The uncharacteristic shape of CP-α could be the result of very closely spaced PR spectra with opposite amplitudes or phases, however impossible to deconvolute. A similar shape, in fact, was observed for polycrystalline Sb 2 Se 3 thin films and for ion beam-synthesized FeSi 2 …”

Section: Resultsmentioning

confidence: 99%

“…A similar shape, in fact, was observed for polycrystalline Sb 2 Se 3 thin films 23 and for ion beam-synthesized FeSi 2 . 24 Temperature-dependent energy positions of all CPs are presented in Figure 2c. CP-γ had the highest energy and a similar temperature dependent trend to CP-β.…”

Section: ■ Resultsmentioning

confidence: 99%

Photoreflectance and Photoluminescence Study of Antimony Selenide Crystals

Kondrotas

Nedzinskas

Krustok

et al. 2022

ACS Appl. Energy Mater.

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Among inorganic, Earth-abundant, and low-toxicity photovoltaic technologies, Sb 2 Se 3 has emerged as a strong material contender reaching over 10% solar cell power conversion efficiency. Nevertheless, the bottleneck of this technology is the high deficit of open-circuit voltage (V OC ) as seen in many other emerging chalcogenide technologies. Commonly, the loss of V OC is related to the nonradiative carrier recombination through defects, but other material characteristics can also limit the achievable V OC . It has been reported that in isostructural compound Sb 2 S 3 , self-trapped excitons are readily formed leading to 0.6 eV Stokes redshift in photoluminescence (PL) and therefore significantly reducing the obtainable V OC . However, whether Sb 2 Se 3 has the same limitations has not yet been examined. In this work, we aim to identify main radiative carrier recombination mechanisms in Sb 2 Se 3 single crystals and estimate if there is a fundamental limit for obtainable V OC . Optical transitions in Sb 2 Se 3 were studied by means of photoreflectance and PL spectroscopy. Temperature, excitation intensity, and polarization-dependent optical characteristics were measured and analyzed. We found that at low temperature, three distinct radiative recombination mechanisms were present and were strongly influenced by the impurities. The most intensive PL emissions were located near the band edge. In conclusion, no evidence of emission from self-trapped excitons or band-tails was observed, suggesting that there is no fundamental limitation to achieve high V OC , which is very important for further development of Sb 2 Se 3 -based solar cells.

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“…An acceptor level in ␤-FeSi 2 is reported by several authors. 35,36 Quantitative details of the energy balance will follow after the interpretation of the excitonic transition 0.809 eV ͑2 K͒. The transition at 0.809 eV, as mentioned above, has a linewidth of 10 meV ͑2 K͒ and, as we have seen in Fig.…”

Section: Resultsmentioning

confidence: 99%

Indirect optical absorption and origin of the emission from β-FeSi2 nanoparticles: Bound exciton (0.809 eV) and band to acceptor impurity (0.795 eV) transitions

Lang

Amaral

Menêses

2010

Journal of Applied Physics

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We investigated the optical absorption of the fundamental band edge and the origin of the emission from β-FeSi2 nanoparticles synthesized by ion-beam-induced epitaxial crystallization of Fe+ implanted SiO2/Si(100) followed by thermal annealing. From micro-Raman scattering and transmission electron microscopy measurements it was possible to attest the formation of strained β-FeSi2 nanoparticles and its structural quality. The optical absorption near the fundamental gap edge of β-FeSi2 nanoparticles evaluated by spectroscopic ellipsometry showed a step structure characteristic of an indirect fundamental gap material. Photoluminescence spectroscopy measurements at each synthesis stage revealed complex emissions in the 0.7–0.9 eV spectral region, with different intensities and morphologies strongly dependent on thermal treatment temperature. Spectral deconvolution into four transition lines at 0.795, 0.809, 0.851, and 0.873 eV was performed. We concluded that the emission at 0.795 eV may be related to a radiative direct transition from the direct conduction band to an acceptor level and that the emission at 0.809 eV derives from a recombination of an indirect bound exciton to this acceptor level of β-FeSi2. Emissions 0.851 and 0.873 eV were confirmed to be typical dislocation-related photoluminescence centers in Si. From the energy balance we determined the fundamental indirect and direct band gap energies to be 0.856 and 0.867 eV, respectively. An illustrative energy band diagram derived from a proposed model to explain the possible transition processes involved is presented.

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Photoreflectance study of ion beam synthesized β-FeSi2

Cited by 7 publications

References 29 publications

Synthesis and characterization of β-phase iron silicide nano-particles by chemical reduction

Synthesis and characterization of β-phase iron silicide nano-particles by chemical reduction

Photoreflectance and Photoluminescence Study of Antimony Selenide Crystals

Indirect optical absorption and origin of the emission from β-FeSi2 nanoparticles: Bound exciton (0.809 eV) and band to acceptor impurity (0.795 eV) transitions

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