Temperature dependence of the fundamental absorption edge in CuGaSe2

Several inorganic perovskites of iodine, bromine, and chlorine halides have emerged as candidates for various optoelectronic devices. Highquality CsPb(I 1−x Br x ) 3 and CsPb(Br 1−x Cl x ) 3 (x = 0.00, 0.25, 0.50, 0.75, and 1.00) inorganic perovskite thin films were prepared in this study using a thermal evaporation system. Experiments and first-principles calculations were conducted to elucidate the structural, electronic, and optical properties of the prepared films at room temperature. The thin-film perovskite band gap was tuned from 1.85 to 3.13 eV by replacing I − with Br − and then Cl − . Dominant excitonic effects on the onset of optical absorption led us to explicitly account for enhancing absorption through the Sommerfield factor, enabling us to extract the electronic band gap and the exciton binding energy correctly. We correlated our experimental results with the theory of first principles and gained insight into the lattice parameters, electronic structure, excitonic binding energy (E b ), dielectric constant (ε), and reduced effective mass (μ) of the carriers. With increasing concentration (x) of Br and Cl, the E b increased from 39.44 meV for pure CsPbI 3 to 63.04 and 96.73 meV for pure CsPbBr 3 and CsPbCl 3 , respectively, because of a decrease in the dielectric constant and the almost constant value of μ at ∼0.051 m e . The Urbach energy (E U ) was calculated and found to fluctuate between 28 and 77 meV.

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“…The optical absorption coefficient (α) was calculated from the optical absorption spectra using the formula 93,94…”

Section: Resultsmentioning

confidence: 99%

“…The optical absorption coefficient (α) was calculated from the optical absorption spectra using the formula , where t denotes the film thickness ( t ≈ 350–450 nm). Therefore, α spectra could be obtained using R and T measurements, as shown in Figure .…”

Section: Results and Discussionmentioning

confidence: 99%

Anion Substitution Effects on the Structural, Electronic, and Optical Properties of Inorganic CsPb(I_1–xBr_x)₃ and CsPb(Br_1–xCl_x)₃ Perovskites: Theoretical and Experimental Approaches

et al. 2021

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“…The value of −(d P E/dT ) decreases with decreasing temperature (−(d P E/dT ) = 0.219 meV K −1 at room temperature, 0.188 meV K −1 at 150 K and 0.149 meV at 100 K, obtained using the Pässler fit). Reported values of −(d E g /dT ) vary from 0.11 [5] (in the range 40-200 K) up to 0.20-0.21 meV K −1 [7,26] (between 100 and 300 K).…”

Section: Equation (1)mentioning

confidence: 99%

Temperature dependence of the exciton gap in monocrystalline CuGaSe₂

Meeder¹,

Jäger-Waldau²,

Arushanov

et al. 2003

J. Phys.: Condens. Matter

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Single crystals of CuGaS 2 have been grown by chemical vapour transport. Their near-band gap photoluminescence properties were investigated in the temperature range of 10-300 K. The variation of the exciton gap energy with temperature was studied by means of a three-parameter thermodynamic model, the Einstein model and the Pássler model. Valúes of the band gap at T=0 K, of a dimensionless constant related to the electron-phonon coupling, and of an effective and a cutoff phonon energy have been estimated. It has also been found that the major contribution of phonons to the shift of £ g as a Keywords: function of T in CuGaS 2 is mainly from optical phonons. Chalcopyrite Photoluminescence Spectroscopy 2.42 2.44 2.46 2.48 2.50 2.52 2.54 2.56 Energy (eV)

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“…The band-gap measurements are typically extracted through optical absorption, photoluminescence (PL), transmittance, and reflection experiments [8][9][10]. Especially, absorption and transmittance experiments are used to measure band-gap energy [11].…”

Section: Introductionmentioning

confidence: 99%

Wide band-gap investigation of modulated BeZnO layers via photocurrent measurement

Kim

Yang

et al. 2012

J Mater Sci

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We grew modulated BeZnO layers by hybrid plasma-assisted molecular-beam epitaxy/electron-beam deposition. A wide band-gap investigation of the modulated Be x Zn 1-x O by means of photocurrent (PC) spectroscopy was conducted. The band-gap energy was directly acquired from the wavelength of the PC peak, caused by the band-to-band transition. By increasing x, which was the rate of the Be elements, the optical band-gap energy was empirically fitted by E BeZnO (x) = 6.32(x-1)x ? 7.305x ? 3.295. We expect that this finding can open new possibilities for wide band-gap engineering of BeZnO layers, which can be utilized as barrier layers in active layers consisting of ZnO/BeZnO quantum well structures and solar-blind ultraviolet photodetectors.

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Temperature dependence of the fundamental absorption edge in CuGaSe2

Cited by 40 publications

References 15 publications

Anion Substitution Effects on the Structural, Electronic, and Optical Properties of Inorganic CsPb(I_1–xBr_x)₃ and CsPb(Br_1–xCl_x)₃ Perovskites: Theoretical and Experimental Approaches

Anion Substitution Effects on the Structural, Electronic, and Optical Properties of Inorganic CsPb(I_1–xBr_x)₃ and CsPb(Br_1–xCl_x)₃ Perovskites: Theoretical and Experimental Approaches

Temperature dependence of the exciton gap in monocrystalline CuGaSe₂

Wide band-gap investigation of modulated BeZnO layers via photocurrent measurement

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Temperature dependence of the fundamental absorption edge in CuGaSe2

Cited by 40 publications

References 15 publications

Anion Substitution Effects on the Structural, Electronic, and Optical Properties of Inorganic CsPb(I1–xBrx)3 and CsPb(Br1–xClx)3 Perovskites: Theoretical and Experimental Approaches

Anion Substitution Effects on the Structural, Electronic, and Optical Properties of Inorganic CsPb(I1–xBrx)3 and CsPb(Br1–xClx)3 Perovskites: Theoretical and Experimental Approaches

Temperature dependence of the exciton gap in monocrystalline CuGaSe2

Wide band-gap investigation of modulated BeZnO layers via photocurrent measurement

Contact Info

Product

Resources

About

Anion Substitution Effects on the Structural, Electronic, and Optical Properties of Inorganic CsPb(I_1–xBr_x)₃ and CsPb(Br_1–xCl_x)₃ Perovskites: Theoretical and Experimental Approaches

Anion Substitution Effects on the Structural, Electronic, and Optical Properties of Inorganic CsPb(I_1–xBr_x)₃ and CsPb(Br_1–xCl_x)₃ Perovskites: Theoretical and Experimental Approaches

Temperature dependence of the exciton gap in monocrystalline CuGaSe₂