Physics Group

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Wavelength dependence of the nonlinear absorption performance and optical limiting in Bi12TiO20 single crystal
(Journal of Luminescence, 2023-01) Işık, Mehmet; Pepe, Yasemin; Karatay, Ahmet; Gasanly, Nizami Mamed; Elmali, Ayhan
In this study, the influence of excitation wavelength and input intensity on the nonlinear absorption (NA) mechanism and optical limiting behavior of the Bi12TiO20 (BTO) single crystal were reported. The energy band gap of the BTO single crystal was obtained to be 2.38 eV. Urbach energy revealed that the single crystal has a highly defective structure. Open aperture (OA) Z-scan experiments were conducted at 532 and 1064 nm excitation wavelengths at various input intensities. Obtained experimental data were analyzed with a theoretical model considering one photon, two-photon and free carrier absorption contributions to NA. The obtained results revealed that the BTO single crystal possesses NA. The NA coefficient increased with increasing input intensity at 532 nm excitation wavelength, while it decreased with increasing input intensity at 1064 nm excitation wavelength. Due to the intense localized defect states distribution at the energy of 532 nm excitation wavelength within the band gap, increasing contribution to NA came from one photon absorption (OPA), sequential two-photon absorption (TPA) and free carrier absorption (FCA) with increasing input intensity. The filling of the defect states at 1064 excitation wavelength caused a reduction in NA due to increasing saturable absorption with increasing input intensity. TPA coefficients were also found from the fitting ignoring the defect states. As expected, the values of the nonlinear absorption coefficient βeff are higher than that of the TPA coefficients for both excitation wavelengths. The optical limiting threshold of the BTO single crystal was obtained to be 6.62 mJ/cm2. The results of the present works indicated that BTO single crystal can be used as a potential optical limiter.
Linear and nonlinear optical properties of Bi12GeO20 single crystal for optoelectronic applications
(Materials Science in Semiconductor Processing, 2023-01) Işık, Mehmet; Gasanly, Nizami Mamed
The present paper aims at presenting linear and nonlinear optical properties of Bi12GeO20 single crystals grown by Czochralski method. Transmission and reflection measurements were performed in the 400-1000 nm region. The recorded spectra were analyzed considering well-known optical models. Spectral dependencies of absorption coefficient, skin depth, refractive index, real and imaginary components of dielectric function were presented. The analyses performed on absorption coefficient showed direct bandgap and Urbach energies as 2.56 and 0.22 eV, respectively. The first- and third-order nonlinear susceptibilities and nonlinear refractive index of the crystal were also reported in the present work. The results of the present paper would provide valuable information for optoelectronic device applications of Bi12GeO20.
Structural and optical properties of (TlInS2)0.75(TlInSe2)0.25 thin films deposited by thermal evaporation
( Journal of Materials Science: Materials in Electronics, 2023-01) Güler, İpek; Işık, Mehmet; Gasanly, Nizami Mamed
Layered semiconductor materials have become a serious research topic in recent years thanks to their effective optical properties. In this article, the thin film structure of Tl2In2S3Se [(TlInS2)0.75(TlInSe2)0.25] material with layered structure was grown by thermal evaporation method. The structural, morphological, and optical properties of the deposited thin films were examined. X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and atomic force microscopy (AFM) techniques were used to get information about structural and morphological properties of the thin films. XRD pattern presented well-defined peaks associated with monoclinic crystalline structure. The crystallite size, dislocation density and lattice strain of the films were also obtained from the analyses of XRD pattern. EDS analysis showed that atomic compositional ratios of the Tl, In, S and Se elements are consistent with chemical formula of Tl2In2S3Se. The optical characterization of thin film was performed using transmission and Raman spectroscopy techniques. Raman spectrum offered information about the vibrational modes of the thin film. The analyses of the transmission spectrum presented the indirect and direct band gap energies of the Tl2In2S3Se thin film as 2.23 and 2.52 eV, respectively. The further analyses on the absorption coefficient resulted in Urbach energy of 0.58 eV.
Investigation of a candidate spin-$\frac{1}{2}$ hidden-charm triple strange pentaquark state $P_{csss}$
(Physical Review D, 2023-01-10) Azizi, Kazım; Saraç, Yasemin; Sundu, Hayriye
A candidate triple strange pentaquark state, $P_{csss}$, is investigated through its strong decay channel $P_{csss} \rightarrow \Omega^-J/\psi $. To calculate the relevant strong coupling constants, two possible interpolating currents with spin-parity $J^P=\frac{1}{2}^{-}$ are used. Though the chosen currents for the state under consideration have spin-parity quantum numbers $J^P=\frac{1}{2}^{-}$, they couple to both the positive and negative parity states simultaneously and the corresponding decay widths are obtained for both parities. These widths are obtained as $\Gamma(P_{csss} \rightarrow J/\psi \Omega^-)=201.4\pm 82.5~\mathrm{MeV}$ for the negative and $\Gamma(\widetilde{P}_{csss} \rightarrow J/\psi \Omega^-)=316.4\pm 107.8~\mathrm{MeV}$ for the positive parity state when the first current is used. For the second current, we obtain $\Gamma(P_{csss} \rightarrow J/\psi \Omega^-)=252.5\pm 116.7~\mathrm{MeV}$ for the negative and $\Gamma(\widetilde{P}_{csss} \rightarrow J/\psi \Omega^-)=361.1\pm 98.4~\mathrm{MeV}$ for the positive parity state. These results may provide insights into future experimental observations of such candidate states and help to distinguish and fix their properties.
Growth and temperature tuned band gap characteristics of NaBi(MoO4)2 single crystal
(Physica Scripta, 2023-02-01) Işık, Mehmet; Güler, İpek; Gasanly, Nizami Mamed
Structural and optical properties of double sodium–bismuth molybdate NaBi(MoO4)2 semiconductor compound was investigated by X-ray diffraction, Raman and transmission experiments. From the X-ray diffraction experiments, the crystal that has tetragonal structure was obtained. Vibrational modes of the crystal were found from the Raman experiments. Transmission experiments were performed in the temperature range of 10-300 K. Derivative spectroscopy analysis and absorption spectrum analysis were performed to get information about the change in band gap energy of the crystal with temperature. It was observed that the band gap energies of the crystal at different temperatures obtained from these techniques are well consisted with each other. By the help of absorption spectrum which was obtained from transmission measurements performed at varying temperatures, absolute zero value of the band gap and average phonon energy as 3.03 ± 0.02 eV and 〈E_ph 〉 = 24 ± 0.2 meV, respectively. Moreover, based on absorption spectrum analysis the Urbach energy of the crystal was obtained as 0.10 eV.
Growth and characterization of PbMo0.75W0.25O4 single crystal: A promising material for optical applications
(Materials Chemistry and Physics, 2023-02-15) Işık, Mehmet; Gasanly, Nizami Mamed; Darvishov, Namiq H.; Bagiev, Vidadi E.
The present paper reports the structural and optical properties of PbMo0.75W0.25O4 single crystals grown by Czochralski method. XRD pattern of the crystal indicated well-defined two diffraction peaks associated with tetragonal crystalline structure. Raman and infrared spectra of the grown single crystals were presented to get information about the vibrational characteristics. Observed Raman modes were associated with modes of PbMoO4 and PbWO4. Eight bands were revealed in the infrared spectrum. The bands observed in the spectrum were attributed to multiphoton absorption processes. Transmission spectrum was measured in the 375-700 nm spectral region. The analyses of the spectrum resulted in direct band gap energy of 3.12 ± 0.03 eV. The compositional dependent band gap energy plot was drawn considering the reported band gap energies of PbMoO4, PbWO4 and revealed band gap of PbMo0.75W0.25O4 single crystal. An almost linear behavior of composition-band gap energy was seen for PbMo1-xWxO4 compounds. Urbach energy was also found from the absorption coefficient analysis as 0.082 ± 0.002 eV.
Growth and characterization of NaBi(Mo0.5W0.5O4)2 single crystal: A promising material for optoelectronic applications
(Materials Science in Semiconductor Processing, 2023-03-15) Işık, Mehmet; Güler, İpek; Gasanly, Nizami Mamed
The structural and optical characteristics of NaBi(Mo0.5W0.5O4)2 single crystals grown by Czochralski method were investigated. X-ray diffraction (XRD) pattern exhibited four well-defined peaks related to tetragonal crystalline structure with a space group I41/a. Raman and infrared transmittance spectra were recorded to investigate vibrational properties of the compound. Room temperature transmission spectrum was measured to reveal band gap energy of the crystal. The derivative spectral and absorption coefficient analyses resulted in direct band gap energy of 3.19 and 3.18 eV, respectively. Urbach energy of the crystal was also determined as 0.17 eV from photon energy dependency of absorption coefficient. The structural and optical parameters obtained for NaBi(Mo0.5W0.5O4)2 were compared with the parameters of the NaBi(XO4)2 (X: Mo,W) compounds to understand the effect of the composition on the studied properties. The reported characteristics of NaBi(Mo0.5W0.5O4)2 point out that the compound has significant potential to be used in optoelectronic devices.
DFT Insights into Noble Gold-Based Compound Li5AuP2: Effect of Pressure on Physical Properties
(ACS Omega (American Chemical Society), 2023-04-20) Sürücü, Gökhan; Gencer, Ayşenur; Sürücü, Özge; Ali, Md. Ashraf
In this study, the Li5AuP2 compound is investigated in detail due to the unique chemical properties of gold that are different from other metals. Pressure is applied to the compound from 0 to 25 GPa to reveal its structural, mechanical, electronic, and dynamical properties using density functional theory (DFT). Within this pressure range, the compound is optimized with a tetragonal crystal structure, making it mechanically and dynam-ically stable above 18 GPa and resulting in an increment of bulk, shear, and Young's moduli of Li5AuP2. Pressure application, furthermore, changes the brittle or ductile nature of the compound. The anisotropic elastic and sound wave velocities are visualized in three dimensions. The thermal properties of the Li5AuP2 compound are obtained, including enthalpy, free energy, entropy x T, heat capacity, and Debye temperature. The electronic properties of the Li5AuP2 compound are studied using the Perdew-Burke-Ernzerhof (PBE) and Heyd-Scuseria-Ernzerhof (HSE) functionals. The pressure increment is found to result in higher band gap values. The Mulliken and bond overlap populations are also determined to reveal the chemical nature of this compound. The optical properties, such as dielectric functions, refractive index, and energy loss function of the Li5AuP2 compound, are established in detail. To our knowledge, this is the first attempt to study this compound in such detail, thus, making the results obtained here beneficial for future studies related to the chemistry of gold.
Physical characterization of thermally evaporated Sn–Sb–Se thin films for solar cell applications
(Applied Physics A, 2023-04-26) Bektaş, Tunç; Sürücü, Özge; Terlemezoğlu, Makbule; Parlak, Mehmet
The substitution of Sb in binary SnSe structure may lead to tailoring the physical properties of both SnSe and SbSe, promising absorber layers for thin film solar cells. The resulting Sn-Sb-Se structure could be an outstanding material for photovoltaic applications. In this study, Sn-Sb-Se thin films were deposited by thermal evaporation, and the effect of annealing on the films' structural, optical, and electrical properties were reported. XRD measurement shows that annealing at 300 degrees C yields the best crystalline quality, and structural parameters were calculated using XRD data. SEM and AFM measurements indicate deformation in the film surface after annealing at 400 degrees C. UV-Vis spectroscopy measurement provides a high absorption coefficient which indicates a direct band gap. The band gap and activation energies of the as-grown sample were found as 1.59 eV and 106.1 meV, respectively. The results of SEM, AFM, XRD, Raman, UV-Vis spectroscopy and temperature-dependent photoconductivity measurements were discussed throughout the paper.
Temperature dependence of band gap of CeO2 nanoparticle photocatalysts
(Physica E: Low-dimensional Systems and Nanostructures, 2023-06) Işık, Mehmet; Delice, Serdar; Gasanly, Nizami Mamed
Cerium dioxide (CeO2) have been one of the attractive photocatalysts material in recent years. Band gap and its change with temperature takes remarkable attention in the photocatalytic applications. The present work reported structural and temperature-dependent band gap characteristics of the CeO2 nanoparticles on glass substrate. X-ray diffraction (XRD) pattern exhibited nine peaks related to face-centered cubic structure. Crystallite size and micro-strain of the nanoparticles were determined from the analyses of XRD peaks. Scanning electron microscope (SEM) image indicated that CeO2 is in the form of nanoparticle with almost cube shaped of diameters in between 20-30 nm. Transmission measurements were performed in the 350-700 nm range at various temperatures between 10-300 K. The analyses of the transmission spectra showed that direct band gap energy decreases from 3.35 to 3.29 eV when sample temperature was raised from 10 K to room temperature. The temperature dependence of band gap energy was analyzed by Varshni expression. The analysis presented absolute zero and rate of change of band gap with temperature as 3.35 eV and −4.7×10-4 eV/K, respectively.
Optical characterization of (TlInS2)0.5(TlInSe2)0.5 crystal by ellipsometry: Linear and optical constants for optoelectronic devices
(Journal of Materials Science: Materials in Electronics, 2023-06) Güler, İpek; Işık, Mehmet; Gasanly, Nizami Mamed
TlInSSe [(TlInS2)0.5(TlInSe2)0.5] crystals have garnered significant attention as promising candidates for optoelectronic applications due to their exceptional optoelectrical characteristics. This study focused on investigating the linear and nonlinear optical properties of TlInSSe layered single crystals through ellipsometry measurements. The X-ray diffraction analysis revealed the presence of four distinct peaks corresponding to a monoclinic crystalline structure. In-depth analysis was conducted to examine the variations of refractive index, extinction coefficient, and complex dielectric function within the energy range of 1.25-6.15 eV. By employing derivative analysis of the absorption coefficient and utilizing the Tauc relation, the indirect and direct bandgap energies of TlInSSe crystals were determined to be 2.09 eV and 2.26 eV, respectively. Furthermore, this research paper presents findings on oscillator energy, dispersion energy, Urbach energy, zero and high frequency dielectric constants, plasma frequency, carrier density to effective mass ratio, nonlinear refractive index, and first-order and third-order nonlinear susceptibilities of TlInSSe crystals.
Spectroscopic Ellipsometry Studies of Optical Properties of TlIn(S0.25Se0.75)2 crystal
(Applied Physics A Materials Science and Processing, 2023-06) Güler, İpek; Işık, Mehmet; Gasanly, Nizami Mamed
The optical properties of TlIn(S0.25Se0.75)2 crystals were studied by ellipsometry measurements. X-ray diffraction pattern presented well-defined peaks associated with monoclinic structure. Energy dependent graphs of various linear optical parameters of the crystal were presented in the 1.25 − 4.50 eV range. The band gap and Urbach energies of the compound were found as 1.96 and 0.68 eV, respectively, from the analyses of the absorption coefficient. Refractive index spectrum was analyzed considering the single-effective-oscillator model to get oscillator and dispersion energies, zero and high frequency dielectric constants, plasma frequency. Moreover, the nonlinear refractive index, first-order and third-order nonlinear susceptibilities of TlIn(S0.25Se0.75)2 crystal were revealed in the present paper.
Excitation wavelength dependent nonlinear absorption mechanisms and optical limiting properties of Bi12SiO20 Single Crystal
(Optical Materials, 2023-06) Dogan, Anıl; Karatay, Ahmet; Işık, Mehmet; Pepe, Yasemin; Gasanly, Nizami Mamed; Elmali, Ayhan
Nonlinear absorption mechanisms (NA), excitation wavelength dependence, and defect states of Bi12SiO20 (BSO) single crystal were investigated. The band gap and Urbach energies were found to be 2.51 and 0.4 eV from the absorption spectra. To evaluate the effect of excitation energy on the NA mechanism of the BSO single crystal, open aperture Z-scan experiment with 4 ns laser pulse at 532 and 1064 nm wavelengths with different intensities was performed. Obtained data were analyzed with a theoretical model considering the contributions of one photon absorption (OPA), two photon absorption (TPA) and free carrier absorption (FCA) to NA. The results indicated that the NA behavior decreased with increasing of the pump intensity as the defect states at around 2.32 eV by OPA at 532 nm, and TPA at 1064 nm excitations. The dominant NA mechanisms are OPA and sequential TPA at 532 nm as compared to the 1064 nm. A higher NA coefficient was obtained at 532 nm as compared to 1064 nm excitation. This observation was attributed to higher contribution of OPA at 532 nm even at lower input intensities compared to TPA contribution at 1064 nm. Onset optical limiting thresholds were found as 0.34 and 0.68 mJ/cm2 for 532 and 1064 nm input beams, respectively. In the light of the results, the BSO single crystal may be used as a saturable absorber or an optical limiter at convenient input intensity by effectively adjusting defect states and excitation wavelength.
Investigation of Tungsten-Based Seleno-Chevrel Compounds with Different Compositions for Efficient Water Splitting
(Advanced Theory and Simulations, 2023-06-29) Dağ, Tuğçe Sevinç; Sürücü, Gökhan; Gencer, Ayşenur; Sürücü, Özge; Özel, Faruk; Çiftçi, Yasemin
This study investigates the photocatalytic water splitting performance for NixW6Se8 (x = 1, 2, 3, 4) Chevrel phases with the chemical formula MxMo6Ch8, where M is a metal and Ch is a chalcogen, with x being 0, 1, 2, 3, or 4. Density Functional Theory (DFT) is used to study the NixW6Se8 (x = 1, 2, 3, 4) Chevrel phases, which includes earth-abundant elements for this specific study as an essential consideration for photocatalytic water splitting. The electronic properties are calculated for the NiW6Se8 and Ni2W6Se8 compounds with thermodynamical, mechanical, and dynamic stabilities. For photocatalytic water splitting, the band gaps below 1.23 eV are excluded, and the conduction and valence band levels are determined to examine the reduction and oxidation potentials for efficient photocatalytic water-splitting materials. An examination of the selected band gaps, along with the conduction and valence band levels, reveals that NiW6Se8 is suitable for both reduction and oxidation reactions; whereas, Ni2W6Se8 is a convenient material only for the reduction reaction. This is the first attempt, as far as the literature reveals, to study Chevrel phases in detail and to identify a suitable compound for photocatalytic water splitting.
Tunable nonlinear absorption and optical limiting behavior of NaBi(MoxW1-xO4)2 single crystals with ratio of Molybdenum/Tungsten
(Physica Scripta, 2023-07-01) Pepe, Yasemin; Yıldız, Elif Akhüseyin; Işık, Mehmet; Karatay, Ahmet; Gasanly, Nizami Mamed; Elmali, Ayhan
The compositional effect of Mo/W ratio on linear, nonlinear absorption and optical limiting behavior of the NaBi(MoxW1-xO4)2 single crystals grown by Czochralski technique was investigated. X-ray diffraction patterns of the studied crystals presented well-defined peaks associated with the tetragonal crystalline structure. The nonlinear absorption performance and optical limiting threshold were determined using an open-aperture Z-scan technique. A theoretical model including one photon absorption (OPA), two photon absorption (TPA) and free carrier absorption was used to determine the nonlinear absorption parameters. All of the results showed that defect states, which strongly affect nonlinear absorption (NA) and optical limiting behaviors, can be tuned with the Mo/W ratio, enabling NaBi(MoxW1-xO4)2 single crystals to be used in desired optoelectronic applications. Linear optical absorption analysis revealed that bandgap energy and defect states can be tuned by changing the Mo/W ratio in the crystal structure. The obtained results showed that all the studied crystals had NA behavior and the nonlinear absorption coefficient decreased with increasing Mo/W ratio. Sequential TPA is the main NA mechanism for these crystals due to the fact that the incident light energy is lower than the bandgap energies and the existence of the real intermediate state around 2.32 eV.
Temperature-dependent current-voltage characteristics of p-GaSe0.75S0.25/n-Si heterojunction
(Applied Physics A Materials Science and Processing, 2023-08) Işık, Mehmet; Sürücü, Özge; Gasanly, Nizami Mamed
GaSe0.75S0.25 having layered structure is a potential semiconductor compound for optoelectronics and two-dimensional materials technologies. Optical and structural measurements of the GaSe0.75S0.25 thin film grown on the glass substrate showed that the compound has hexagonal structure and band energy of 2.34 eV. GaSe0.75S0.25 thin film was also grown on the silicon wafer and p-GaSe0.75S0.25/n-Si heterojunction was obtained. In order to make the electrical characterization of this diode, temperature-dependent current-voltage (I-V) measurements were carried out between 240-360 K. Room temperature ideality factor and barrier height of the device were determined from the analyses of I-V plot as 1.90 and 0.87 eV, respectively. Temperature-dependent plots of these electrical parameters showed that the ideality factor decreases from 2.19 to 1.77, while barrier height increases to 0.94 from 0.71 eV when the temperature was increased from 240 to 360 K. The conduction mechanism in the heterojunction was studied considering the Gaussian distribution due to presence of inhomogeneity in barrier height. The analyses presented the mean zero-bias barrier height, zero-bias standard deviation, and Richardson constant.
Growth and temperature-tuned band gap characteristics of LiGd(MoO4)2 single crystals for optoelectronic applications
(Ceramics International, 2023-08-01) Delice, Serdar; Işık, Mehmet; Gasanly, Nizami Mamed; Darvishov, Namiq H.; Bagiev, Vidadi E.
LiGd(MoO4)2 has been investigated due to its optoelectronic applications, especially for development of light-emitting diodes. In the present paper, LiGd(MoO4)2 single crystals grown by Czochralski method was studied in terms of structural and temperature dependent optical properties. X-ray diffraction analysis showed that the crystal crystallizes in a single phase tetragonal structure. Raman spectrum exhibited six distinguishable peaks around 207, 319, 397, 706, 756 and 890 cm−1. These peaks correspond to vibrational modes of free rotation, symmetrical stretching, symmetric bending, antisymmetric stretching and antisymmetric bending of (MoO4)2− tetrahedron. Infrared transmittance spectrum had six minima around 2114, 2350, 2451, 2854, 2929, 2960, 3545 and 3578 cm−1 which are due to multiphonon absorptions. Spectral change of transmittance curves at various temperature between 10 and 300 K was utilized to elucidate temperature effect on absorption characteristics. Optical band gap of the material was found using Tauc and spectral derivative methods. The band gap value was obtained as 3.09 eV at room temperature and this value increased to 3.22 eV with decreasing temperature down to 10 K. The detailed analysis on the temperature dependency of the band gap was applied by Varshni model and the band gap at 0 K and change of rate of the band gap were estimated as 3.23 eV and −1.45 × 10−3 eV/K, respectively. Room temperature photoluminescence spectrum of the crystal presented a peak around 709 nm which corresponds to red light emission. LiGd(MoO4)2 is a potential candidate for optoelectronic devices emitting red light.
Temperature-Dependent Optical Properties of TiO2 Nanoparticles: A Study of Band Gap Evolution
(Optical and Quantum Electronics, 2023-10) Işık, Mehmet; Delice, Serdar; Gasanly, Nizami Mamed
In this study, we present the first comprehensive investigation of the temperature-dependent band gap energy of anatase TiO2 nanoparticles, utilizing transmission measurements in the range of 10-300 K. X-ray diffraction pattern exhibited nine peaks related to tetragonal crystal structure. Scanning electron microscope image showed that the nanoparticles with the dimensions of 25-50 nm were found as micrometer sized agglomerated. When the spectrum obtained as a result of the transmission measurements was analyzed, it was seen that the band gap energy decreased from 3.29(5) to 3.26(6) eV as the temperature was increased from 10 K to 300 K. Temperature-band gap dependence was analyzed using Varshni and O'Donnell-Chen optical models and optical parameters of the TiO2 nanoparticles like absolute zero band gap energy, rate of change of band gap with temperature and average phonon energy were reported.
Investigation of the strange pentaquark candidate P_{\psi s}(4338)^0 recently observed by LHCb
(Physical Review D., 2023-10-01) Azizi, Kazım; Saraç, Yasemin; Sundu, Hayriye
The recently observed strange pentaquark candidate, PΛψs(4338)0, is investigated to provide information about its nature and substructure. To this end, its mass and width through the decay channels PΛψs(4338)0→J/ψΛ and PΛψs(4338)0→ηcΛ are calculated by applying two- and three-point QCD sum rules, respectively. The state is considered as a Ξc¯D meson-baryon molecular structure with spin-parity quantum numbers JP=12−. The obtained mass, mPΛψs(4338)0=4338±130 MeV, and width, ΓPΛψs(4338)0=10.40±1.93 MeV, are consistent with the experimental data within the presented uncertainties. This allows us to assign a Ξc¯D molecular structure of JP=12− for the PΛψs(4338)0 state.
Nanowire geometry effects on devices and transport mechanisms: SnS2/SiNW heterojunction
(Journal of Materials Science, 2023-10-04) Coskun, Emre; Emir, Cansu; Terlemezoğlu, Makbule; Parlak, Mehmet
The semiconductor nanowire technology has become essential in developing more complex and efficient devices. In this study, the Si nanowire (SiNW) heterojunction structure with a two-dimensional SnS2 thin film was investigated. The SiNW array was created by the metal-assisted etching method because of length control and production over large areas of nanowires. The created SiNW has more diminishing reflectivity compared with Si planar substrate. The diode characteristics of SnS2/SiNW and SnS2/Si planar heterojunctions were investigated by dark current analysis at room temperature, and the improving diode characteristics by the three-dimensional interface between SiNW and SnS2 thin film were discussed. Transport mechanisms of the SiNW heterojunction were also studied for various methods. Thermionic emission and thermally assisted tunneling models are the dominant mechanisms for low voltages (0.02–0.20 V), and the space charge limiting current mechanism dominates the current for comparingly high voltages (0.20–0.40 V). All the values reveal the significant impact of the SiNW on heterojunctions for improving efficiency.

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