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The investigations on optical properties of TiN C ternary alloys
摘要： Under the first-principles framework, this paper used the CASTEP program to theoretically calculate TiN, TiC, and its intermediate compounds and therefore obtain a theoretical basis for their application. In this paper, the N atoms in the NaCl-type unit cell of TiN were replaced, and the atoms of TiN1-xCx (x = 0.25, 0.5, and 0.75) were constructed by replacing N with C atoms. The unit cell structure of the ternary compound TiN1-xCx (x = 0.25, 0.5, and 0.75) was constructed by replacing N with C atoms. In a subsequent step, these compounds were geometrically optimized and their properties were calculated. These compounds were subsequently subjected to geometric optimization to calculate their properties. By analyzing the electronic structure of the materials, it was found that TiN1-xCx exhibited metallic properties. In addition, this paper focused on the optical properties of TiN1-xCx ternary compounds under different compositions including absorption, reflectivity, refractive index, and photoconductivity. The accuracy and reliability of the theoretical results presented herein were confirmed by comparing current theoretical results with existing experimental or theoretical results.
关键词： TiN1-xCx alloys,First principles calculations,Optical properties
更新于2025-09-10 09:29:36
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Surfactant-induced chemical ordering of GaAsN:Bi
摘要： We have examined the in?uence of an incorporating surfactant on chemical ordering in GaAsN:Bi alloys. Epitaxy with a (2 (cid:2) 1) reconstruction leads to the formation of GaAsN alloys, while the introduction of a Bi ?ux induces long-range chemical ordering of the {111} planes of GaAsN:Bi. We propose a mechanism in which Bi enhances the alignment of dimer rows along the [110] direction, facilitating N incorporation beneath surface dimers and Bi incorporation between dimer rows to form alternating N-rich and Bi-rich {111} planes. These ?ndings suggest a route to tailoring the local atomic environment of N and Bi atoms in a wide range of emerging dilute nitride-bismide alloys.
关键词： surfactant,molecular-beam epitaxy,chemical ordering,dilute nitride-bismide alloys,GaAsN:Bi
更新于2025-09-10 09:29:36
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Smart Materials and Structures: State of the Art and Applications
摘要： The world of materials is an exciting and challenging field of research since it has always played a dominant role in the evolution of human civilization. The demands from aerospace, defence, automotive and industrial branches on more advanced and innovative materials has led to the development of a new generation of materials with much better performance and capabilities than the existing conventional structural and functional materials. As a result, the era of smart materials has started. Smart materials can change their physical properties in response to a specific stimulus input. However, there is still a blurry image over the types and potential applications of smart materials. The objective of this paper is to define the field of smart materials and structures, together with its current status and potential benefits. However, more focus will be devoted to piezoelectric materials and results are presented and discussed. Finally, and in order to demonstrate the characteristics of one class of smart materials, two numerical examples are proposed and results are presented.
关键词： Piezoelectric materials,Actuators and sensors,Smart materials,Shape memory alloys
更新于2025-09-10 09:29:36
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Electronic transport properties of (Se80Te20)100?xZnx (2?≤?x?≤?6) chalcogenide alloys
摘要： The bulk chalcogenide (Se80Te20)100-xZnx (2≤x≤6) alloys are prepared using melt quenching technique and electronic transport properties are studied in the frequency range 50 Hz–500 KHz and temperature range 400-520 K. The sharp peaks observed in X-ray diffraction pattern indicate the polycrystalline nature of prepared compositions. The measured dielectric properties and a.c. conductivity reveal the significant influence of Zn doping on the properties of the Se-Te matrix. The a.c. conductivity obeys Jonscher power law as ~ w s (s<1). To describe the conduction mechanism, the experimental results are analyzed in the framework of various theoretical models. The correlated barrier hopping (CBH) model successfully describe the observed frequency, temperature and composition response of ac conductivity.
关键词： a.c. conductivity,electronic transport properties,Chalcogenide alloys,dielectric constant,dielectric loss,X-Ray diffraction
更新于2025-09-09 09:28:46
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Alloy-assisted Auger recombination in InGaN
摘要： It has been numerically investigated the effect of alloying on the Auger recombination rate in wurtzite type n-InGaN. In order to explicitly take into account the effect of alloy disorder, the calculations have been performed with a 256-atom supercell that includes In and Ga atoms randomly distributed over the supercell sites to obtain a given composition. A full band structure (no band scissors-shifting) and high-dense inhomogeneous k-point grid were used to improve the accuracy of the calculations. We show that the large number of allowed interband Auger transitions originated by the breaking of the translational periodicity plays a crucial role in the wide band gap InGaN alloys. The alloy-assisted Auger coefficients for these alloys are in the 1.0 × 10?32–4.7 × 10?31 cm6/s range
关键词： InGaN alloys,Atomic disorder,Supercell,Auger recombination
更新于2025-09-09 09:28:46
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Noise Analysis of Group IV Material-Based Heterojunction Phototransistor for Fiber-Optic Telecommunication Networks
摘要： This paper presents an analytical study of noise behavior and spectral responsivity of Ge1?xSnx alloy-based heterojunction phototransistors (HPTs) for different Sn compositions and base doping concentrations. The structure consists of n-Ge/p-Ge1?xSnx layers pseudomorphically grown on Si substrate via Ge virtual substrate, compatible with complementary metal-oxide-semiconductor technology. The high absorption coefficient of the alloy in base significantly improves signal-to-noise ratio in the high-frequency region, leading to efficient photodetection in the C- and L-bands of fiber-optic telecommunication window. A comparison is made between the theoretical findings for GeSn HPTs and the available data for currently employed group III–V compound-based HPTs, to examine if GeSn-based HPT can be a good alternative.
关键词： GeSn alloys,absorption coefficient,spectral responsivity,heterojunction phototransistor,signal-to-noise ratio
更新于2025-09-09 09:28:46
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Comprehensive Analysis and Optimal Design of Ge/GeSn/Ge p-n-p Infrared Heterojunction Phototransistors
摘要： We present a comprehensive analysis of practical p-n-p Ge/Ge1?xSnx/Ge heterojunction phototransistors (HPTs) for design optimization for efficient infrared detection. Our design includes a Ge1?xSnx narrow-bandgap semiconductor as the active layer in the base layer, enabling extension of the photodetection range from near-infrared to mid-infrared to perform wide-range infrared detection. We calculate the current gain, signal-to-noise ratio (SNR), and optical responsivity and investigate their dependences on the structural parameters to optimize the proposed Ge1?xSnx p-n-p HPTs. The results show that the SNR is strongly dependent on the operation frequency and that the introduction of Sn into the base layer can improve the SNR in the high-frequency region. In addition, the current gain strongly depends on the Sn content in the Ge1?xSnx base layer, and a Sn content of 6%–9% maximizes the optical responsivity achievable in the infrared range. These results provide useful guidelines for designing and optimizing practical p-n-p Ge1?xSnx HPTs for high-performance infrared photodetection.
关键词： current gain,sign-to-noise ratio,infrared,heterojunction phototransistors,GeSn alloys
更新于2025-09-09 09:28:46
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Ge-Rich Graded-Index SiGe Alloys: Exploring a Versatile Platform for mid-IR Photonics
摘要： In this paper, the recent progress on a new Ge-rich SiGe platform for mid-IR integrated photonics is presented. Low-loss spiral waveguides working over a broadband wavelength range are discussed, followed by a sensing proof-of-concept using a standalone photoresist with a known spectral absorption pattern. In addition, the development of new mid-IR interferometric devices for wavelength filtering and enhancement of the light-matter interaction are presented. Finally, efficient designs to exploit the third-order nonlinearities in these Ge-rich SiGe waveguides at mid-IR wavelengths are shown. The demonstration of these key building blocks will pave the way towards the implementation of new mid-IR photonic integrated systems with multiple functionalities.
关键词： waveguides,non-linear mid-IR photonics,interferometric optical devices,mid-IR integrated photonics,SiGe alloys,mid-IR spectroscopy
更新于2025-09-09 09:28:46
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Electron Structure and Optical Properties of the Mn1.8Co1.2Al Alloy and Spin Gapless Semiconductor State
摘要： This paper studies the optical properties of the Mn1.8Co1.2Al alloy, whose composition is close to that of spin gapless Mn2CoAl semiconductor. Our investigation found the absence of intraband absorption contribution, which is an anomalous behavior of optical properties of the alloy. The presence of intense interband absorption in the IR range of spectrum indicates the existence of low-energy gap in the band spectrum of the alloy, which was found by electron structure calculations of the Mn1.75Co1.25Al alloy.
关键词： electron structure,Heusler alloys,optical properties
更新于2025-09-09 09:28:46
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Structural Characterization of Two New Quaternary Chalcogenides: CuCo2InTe4 and CuNi2InTe4
摘要： The crystal structure of the chalcogenide compounds CuCo2InTe4 and CuNi2InTe4, two new members of the I-II2-III-VI4 family, were characterized by Rietveld refinement using X-ray powder diffraction data. Both materials crystallize in the tetragonal space group I 4 2m (No. 121), Z = 2, with a stannite-type structure, with the binaries CoTe and NiTe as secondary phases.
关键词： structural characterization,chemical synthesis,alloys,semiconductors,X-ray powder diffraction
更新于2025-09-09 09:28:46