Thermally stimulated current spectroscopy of traps in CVD grown monolayer MoS2

Deb, Swarup; Chakrabarti, Poulab; Chakraborti, Himadri; Gupta, K. Das; Dhar, Subhabrata

doi:10.1063/1.5094153

Cited by 4 publications

(3 citation statements)

References 27 publications

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“…The deeper defect corresponding to the energy of 885 meV and 822 meV in natural and synthetic MoS 2 flake devices appears to have the same origin. These measured values are in good agreement with the values reported by Deb et al [17]. They measured two traps with average activation energies of 670 and 850 meV by thermal stimulation current (TSC) measurements in CVD-grown monolayer MoS 2 samples and assigned these two activation energies to S-vacancies.…”

Section: Resultssupporting

confidence: 90%

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Defect density of states in natural and synthetic MoS₂ multilayer flakes

Srivastava¹,

Mohapatra²

2022

J. Phys. D: Appl. Phys.

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It has become important to identify and study dominant defects in TMDC (transition metal di-chalcogenide) materials in different forms being explored for use in electronic devices. We have investigated the density and distribution of deep defect states in natural and synthetic multilayer MoS2 (m-MoS2) flakes using temperature-dependent admittance spectroscopy. The flakes sandwiched between suitable electrodes with structure Au|m-MoS2|ZnO act as good quality diodes suitable for capacitance-based studies. The defect density of states shows Gaussian distribution, and density was found to be approximately 1014 and 1013 cm-3eV-1 in the natural and synthetic MoS2 flake devices, respectively. Both types of flakes showed a deep level around 0.8 eV below the conduction band edge with a Gaussian disorder parameter of around 33 and 30 meV respectively at room-temperature, indicating the common origin corresponding to these defect states. Synthetic MoS2 flake device shows the appearance of an additional defect state at around 0.7 eV which is probably related to a stoichiometric defect. Our results point to possible occurrence of large lattice relaxation of donors with associated trap levels deep within the gap. Our results demonstrate an excellent non-destructive method of deriving defect density of states in multilayer flakes.

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Section: Resultssupporting

confidence: 90%

“…Recently, electron paramagnetic resonance and thermally stimulated current (TSC) measurements were performed to investigate defect states in bulk crystals [14,17]. However, a systematic characterization and estimation of the energetic position of defect density of states (DOS) in MoS 2 has not been reported.…”

Section: Introductionmentioning

confidence: 99%

Defect density of states in natural and synthetic MoS₂ multilayer flakes

Srivastava¹,

Mohapatra²

2022

J. Phys. D: Appl. Phys.

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“…The novelty of our work is that we utilized the fitting error of the Schottky diode I-V curve not as a by-product but as a key role for diagnosing the characteristic peak position and the number of deep levels of DLTS analysis. Finally, we also compared our method with other methods like TSC [28][29][30] (or TSCAP [30][31][32]), which might be considered auxiliary tools for DLTS. It is thought that the methodology of this study will help to utilize DLTS more efficiently in the industrial environment.…”

Section: Introductionmentioning

confidence: 99%

Auxiliary Diagnostic Signal for Deep-Level Detection

Ahn,

Lee,

Kim

2023

Nanomaterials

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We propose and demonstrate that temperature-dependent curve-fitting error values of the Schottky diode I–V curve in the forward regime can be an auxiliary diagnostic signal as the temperature-scan Capacitance DLTS (CDLTS) signals and helps to work time-efficiently with high accuracy when using the Laplace Transform (LT)–DLTS or Isothermal Capacitance transient spectroscopy (ICTS) method. Using Be-doped GaAs showing overlapping DLTS signals, we verify that the LT–DLTS or ICTS analysis within a specific temperature range around the characteristic temperature Tpeak coincides well with the results of the CDLTS and Fourier Transform DLTS performed within the whole temperature range. In particular, we found that the LT–DLTS signals appeared intensively around Tpeak, and we confirmed it with the ICTS result. The occurrence of the curve fitting error signal is attributed to the relatively increased misfit error by the increased thermal emission from the deep-level trap in the case near the Tpeak, because the applied transport model excludes defect characteristics.

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Enhancement of valley polarization in CVD grown monolayer MoS2 films

Chakrabarti

Mujeeb

Dhar

2022

Applied Physics Letters

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The development of future valley based electronics or valleytronics requires a high degree of valley polarization (VP) in large area monolayer (1L)-MoS2. Though it is possible to synthesize 1L-MoS2 films with large area coverage, VP property of as-grown films is found to be very poor. Here, we investigate the role of physisorbed air molecules and strain on the luminescence and the VP characteristics of large area monolayer MoS2 grown on various substrates by a microcavity based chemical vapor deposition (CVD) technique. The study shows that the removal of adsorbates from sulfur vacancy ( VS) sites not only suppresses the broad sub-bandgap luminescence feature that typically dominates low temperature photoluminescence (PL) spectra of these films but also significantly enhances VP. Post-growth transfer of the 1L-MoS2 film from sapphire to a SiO2/Si substrate by a polystyrene assisted process is found to be highly effective in improving the polarization characteristic (∼80%) of K-valleys through relaxation of the biaxial tensile strain and the removal of physisorbed air molecules from the VS sites. The process is also found to provide long lasting protection for MoS2 films from air. The finding, thus, creates much needed opportunity to use CVD grown large area 1L-MoS2 for realization of valleytronics of the future.

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Thermally stimulated current spectroscopy of traps in CVD grown monolayer MoS2

Cited by 4 publications

References 27 publications

Defect density of states in natural and synthetic MoS₂ multilayer flakes

Defect density of states in natural and synthetic MoS₂ multilayer flakes

Auxiliary Diagnostic Signal for Deep-Level Detection

Enhancement of valley polarization in CVD grown monolayer MoS2 films

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Thermally stimulated current spectroscopy of traps in CVD grown monolayer MoS2

Cited by 4 publications

References 27 publications

Defect density of states in natural and synthetic MoS2 multilayer flakes

Defect density of states in natural and synthetic MoS2 multilayer flakes

Auxiliary Diagnostic Signal for Deep-Level Detection

Enhancement of valley polarization in CVD grown monolayer MoS2 films

Contact Info

Product

Resources

About

Defect density of states in natural and synthetic MoS₂ multilayer flakes

Defect density of states in natural and synthetic MoS₂ multilayer flakes