Micromachines

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8 pages, 4399 KiB

Open AccessCommunication

Simulation on an Advanced Double-Sided Cooling Flip-Chip Packaging with Diamond Material for Gallium Oxide Devices

by He Guan, Dong Wang, Wentao Li, Duo Liu, Borui Deng and Xiang Qu

Micromachines 2024, 15(1), 98; https://doi.org/10.3390/mi15010098 - 03 Jan 2024

Viewed by 922

Gallium oxide (Ga₂O₃) devices have shown remarkable potential for high-voltage, high-power, and low-loss power applications. However, thermal management of packaging for Ga₂O₃ devices becomes challenging due to the significant self-heating effect. In this paper, an advanced [...] Read more.

Gallium oxide (Ga₂O₃) devices have shown remarkable potential for high-voltage, high-power, and low-loss power applications. However, thermal management of packaging for Ga₂O₃ devices becomes challenging due to the significant self-heating effect. In this paper, an advanced double-sided cooling flip-chip packaging structure for Ga₂O₃ devices was proposed and the overall packaging of Ga₂O₃ chips was researched by simulation in detail. The advanced double-sided cooling flip-chip packaging structure was formed by adding a layer of diamond material on top of the device based on the single-sided flip-chip structure. With a power density of 3.2 W/mm, it was observed that the maximum temperature of the Ga₂O₃ chip with the advanced double-sided cooling flip-chip packaging structure was 103 °C. Compared with traditional wire bonding packaging and single-sided cooling flip-chip packaging, the maximum temperature was reduced by about 12 °C and 7 °C, respectively. When the maximum temperature of the chip was controlled at 200 °C, the Ga₂O₃ chip with double-sided cooling packaging could reach a power density of 6.8 W/mm. Finally, by equipping the top of the package with additional water-cooling equipment, the maximum temperature was reduced to 186 °C. These findings highlight the effectiveness of the proposed flip-chip design with double-sided cooling in enhancing the heat dissipation capability of Ga₂O₃ chips, suggesting promising prospects for this advanced packaging structure. Full article

(This article belongs to the Special Issue Semiconductors and Nanostructures for Electronics and Photonics)

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11 pages, 4102 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Construction of MoS₂-ReS₂ Hybrid on Ti₃C₂T_x MXene for Enhanced Microwave Absorption

by Xiaoxuan Xu, Youqiang Xing and Lei Liu

Micromachines 2023, 14(11), 1996; https://doi.org/10.3390/mi14111996 - 27 Oct 2023

Viewed by 803

Abstract

Utilizing interface engineering to construct abundant heterogeneous interfaces is an important means to improve the absorbing performance of microwave absorbers. Here, we have prepared the MXene/MoS₂-ReS₂ (MMR) composite with rich heterogeneous interfaces composed of two-dimensional Ti₃C₂Tx [...] Read more.

Utilizing interface engineering to construct abundant heterogeneous interfaces is an important means to improve the absorbing performance of microwave absorbers. Here, we have prepared the MXene/MoS₂-ReS₂ (MMR) composite with rich heterogeneous interfaces composed of two-dimensional Ti₃C₂Tx MXene and two-dimensional transition metal disulfides through a facile hydrothermal process. The surface of MXene is completely covered by nanosheets of MoS₂ and ReS₂, forming a hybrid structure. MRR exhibits excellent absorption performance, with its strongest reflection loss reaching −51.15 dB at 2.0 mm when the filling ratio is only 10 wt%. Meanwhile, the effective absorption bandwidth covers the range of 5.5–18 GHz. Compared to MXene/MoS₂ composites, MRR with a MoS₂-ReS₂ heterogeneous interface exhibits stronger polarization loss ability and superior absorption efficiency at the same thickness. This study provides a reference for the design of transition metal disulfides-based absorbing materials. Full article

(This article belongs to the Special Issue Semiconductors and Nanostructures for Electronics and Photonics)

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11 pages, 2875 KiB

Open AccessArticle

Composition Engineering of Indium Zinc Oxide Semiconductors for Damage-Free Back-Channel Wet Etching Metallization of Oxide Thin-Film Transistors

by Xuan Zhang and Sung Woon Cho

Micromachines 2023, 14(10), 1839; https://doi.org/10.3390/mi14101839 - 27 Sep 2023

Cited by 1 | Viewed by 1176

Abstract

In contrast to lift-off and shadow mask processes, the back-channel wet etching (BCWE) process is suitable for industrial-scale metallization processes for the large-area and mass production of oxide thin-film transistors (TFTs). However, chemical attacks caused by the corrosive metal etchants used in the [...] Read more.

In contrast to lift-off and shadow mask processes, the back-channel wet etching (BCWE) process is suitable for industrial-scale metallization processes for the large-area and mass production of oxide thin-film transistors (TFTs). However, chemical attacks caused by the corrosive metal etchants used in the BCWE process cause unintended performance degradation of oxide semiconductors, making it difficult to implement oxide TFT circuits through industrial-scale metallization processes. Herein, we propose composition engineering of oxide semiconductors to enhance the chemical durability and electrical stability of oxide semiconductors. The chemical durability of InZnO against Al etchants can be improved by increasing the content of indium oxide, which has a higher chemical resistance than zinc oxide. As a result, A damage-free BCWE-based metallization process was successfully demonstrated for oxide TFTs using In-rich InZnO semiconductors. Furthermore, In-rich InZnO TFTs with wet-etched Al electrodes exhibited electrical performance comparable to that of lift-off Al electrodes, without chemical attack issues. Full article

(This article belongs to the Special Issue Semiconductors and Nanostructures for Electronics and Photonics)

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10 pages, 9294 KiB

Open AccessCommunication

A Novel Silicon Forward-Biased PIN Mach–Zehnder Modulator with Two Operating States

by Hang Yu, Donghe Tu, Xingrui Huang, Yuxiang Yin, Zhiguo Yu, Huan Guan, Lei Jiang and Zhiyong Li

Micromachines 2023, 14(8), 1608; https://doi.org/10.3390/mi14081608 - 15 Aug 2023

Viewed by 1110

Abstract

In this paper, we demonstrate a silicon forward-biased positive intrinsic negative (PIN) Mach–Zehnder modulator (MZM), which has two operating states of high efficiency and high speed. The two operating states are switched by changing the position where the electric signal is loaded. The [...] Read more.

In this paper, we demonstrate a silicon forward-biased positive intrinsic negative (PIN) Mach–Zehnder modulator (MZM), which has two operating states of high efficiency and high speed. The two operating states are switched by changing the position where the electric signal is loaded. The modulator incorporates a PIN phase shifter integrated with the passive resistance and capacitance (RC) equalizer (PIN-RC), which expands the electro-optic (E-O) bandwidth by equalizing it with modulation efficiency. The fabricated modulator exhibits a low insertion loss of 1.29 dB in two operating states and a compact design with a phase shifter length of 500

μ

m. The modulation efficiencies are 0.0088 V·cm and 1.43 V·cm, and the corresponding 3 dB E-O bandwidths are 200 MHz and 7 GHz, respectively. The high-speed modulation performance of the modulator is confirmed by non-return-to-zero (NRZ) modulation with a data rate of 15 Gbps without any pre-emphasis or post-processing. The presented modulator shows functional flexibility, low insertion loss, and a compact footprint, and it can be suitable for applications like optical switch arrays and analog signal processing. Full article

(This article belongs to the Special Issue Semiconductors and Nanostructures for Electronics and Photonics)

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16 pages, 7155 KiB

Open AccessArticle

Sonochemistry of Liquid-Metal Galinstan toward the Synthesis of Two-Dimensional and Multilayered Gallium-Based Metal–Oxide Photonic Semiconductors

by Mohammad Karbalaei Akbari, Nasrin Siraj Lopa and Serge Zhuiykov

Micromachines 2023, 14(6), 1214; https://doi.org/10.3390/mi14061214 - 08 Jun 2023

Cited by 2 | Viewed by 1122

Abstract

The scientific field of two-dimensional (2D) nanostructures has witnessed tremendous development during the last decade. To date, different synthesis approaches have been developed; therefore, various exceptional properties of this family of advanced materials have been discovered. It has recently been found that the [...] Read more.

The scientific field of two-dimensional (2D) nanostructures has witnessed tremendous development during the last decade. To date, different synthesis approaches have been developed; therefore, various exceptional properties of this family of advanced materials have been discovered. It has recently been found that the natural surface oxide films of room-temperature liquid metals is an emerging platform for the synthesis of novel types of 2D nanostructures with numerous functional applications. However, most of the developed synthesis techniques for these materials are based on the direct mechanical exfoliation of 2D materials as research targets. This paper reports a facile and functional sonochemical-assisted approach for the synthesis of 2D hybrid and complex multilayered nanostructures with tunable characteristics. In this method, the intense interaction of acoustic waves with microfluidic gallium-based room-temperature liquid galinstan alloy provides the activation energy for synthesis of hybrid 2D nanostructures. The microstructural characterizations reveal the impact of sonochemical synthesis parameters, including the processing time and composition of the ionic synthesis environment, on the growth of Ga_xO_y/Se 2D hybrid structures and InGa_xO_y/Se multilayered crystalline structures with tunable photonic characteristics. This technique shows promising potential for synthesis of various types of 2D and layered semiconductor nanostructures with tunable photonic characteristics. Full article

(This article belongs to the Special Issue Semiconductors and Nanostructures for Electronics and Photonics)

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15 pages, 13632 KiB

Open AccessArticle

An Experimental Study of Dislocation Dynamics in GaN

by Eugene B. Yakimov, Yury O. Kulanchikov and Pavel S. Vergeles

Micromachines 2023, 14(6), 1190; https://doi.org/10.3390/mi14061190 - 02 Jun 2023

Cited by 1 | Viewed by 1291

Abstract

The dynamics of dislocations introduced through indentation or scratching at room temperature into a few GaN layers that were grown using the HVPE, MOCVD and ELOG methods and had different dislocation densities were studied via the electron-beam-induced current and cathodoluminescence methods. The effects [...] Read more.

The dynamics of dislocations introduced through indentation or scratching at room temperature into a few GaN layers that were grown using the HVPE, MOCVD and ELOG methods and had different dislocation densities were studied via the electron-beam-induced current and cathodoluminescence methods. The effects of thermal annealing and electron beam irradiation on dislocation generation and multiplication were investigated. It is shown that the Peierls barrier for dislocation glide in GaN is essentially lower than 1 eV; thus, it is mobile even at room temperature. It is shown that the mobility of a dislocation in the state-of-the-art GaN is not entirely determined by its intrinsic properties. Rather, two mechanisms may work simultaneously: overcoming the Peierls barrier and overcoming localized obstacles. The role of threading dislocations as effective obstacles for basal plane dislocation glide is demonstrated. It is shown that under low-energy electron beam irradiation, the activation energy for the dislocation glide decreases to a few tens of meV. Therefore, under e-beam irradiation, the dislocation movement is mainly controlled by overcoming localized obstacles. Full article

(This article belongs to the Special Issue Semiconductors and Nanostructures for Electronics and Photonics)

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13 pages, 5097 KiB

Open AccessArticle

Boosting the Performance of Perovskite Solar Cells through Systematic Investigation of the Annealing Effect of E-Beam Evaporated TiO₂

by Tao Xue, Dandan Chen, Ting Li, Xingxing Chou, Xiao Wang, Zhenyu Tang, Fanghui Zhang, Jin Huang, Kunping Guo and Ashkan Vakilipour Takaloo

Micromachines 2023, 14(6), 1095; https://doi.org/10.3390/mi14061095 - 23 May 2023

Cited by 2 | Viewed by 1307

Abstract

Electron transport layer (ETL) plays an undeniable role in improving the performance of n-i-p planar perovskite solar cells (PSCs). Titanium dioxide (TiO₂) is known as a promising ETL material for perovskite solar cell. In this work, the effect of annealing temperature [...] Read more.

Electron transport layer (ETL) plays an undeniable role in improving the performance of n-i-p planar perovskite solar cells (PSCs). Titanium dioxide (TiO₂) is known as a promising ETL material for perovskite solar cell. In this work, the effect of annealing temperature on optical, electrical, and surface morphology of the electron-beam (EB)-evaporated TiO₂ ETL, and consequently on the performance of perovskite solar cell, was investigated. It was found that annealing treatment at an optimized temperature of 480 °C considerably improved the surface smoothness, density of grain boundaries, and carrier mobility of TiO₂ film, which resulted in nearly 10-fold improvement in power conversion efficiency (11.16%) in comparison with the unannealed device (1.08%). The improvement in performance of the optimized PSC is attributed to the acceleration of charge carrier extraction, as well as suppression of the recombination at the ETL/Perovskite interface. Full article

(This article belongs to the Special Issue Semiconductors and Nanostructures for Electronics and Photonics)

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11 pages, 4030 KiB

Open AccessArticle

Upconversion Luminescence Response of a Single YVO₄:Yb, Er Particle

by Dmitry K. Zharkov, Andrey V. Leontyev, Artemi G. Shmelev, Larisa A. Nurtdinova, Anton P. Chuklanov, Niaz I. Nurgazizov and Victor G. Nikiforov

Micromachines 2023, 14(5), 1075; https://doi.org/10.3390/mi14051075 - 19 May 2023

Cited by 2 | Viewed by 1382

Abstract

We present the results of the luminescence response studies of a single YVO₄:Yb, Er particle of 1-µm size. Yttrium vanadate nanoparticles are well-known for their low sensitivity to surface quenchers in water solutions which makes them of special interest for biological [...] Read more.

We present the results of the luminescence response studies of a single YVO₄:Yb, Er particle of 1-µm size. Yttrium vanadate nanoparticles are well-known for their low sensitivity to surface quenchers in water solutions which makes them of special interest for biological applications. First, YVO₄:Yb, Er nanoparticles (in the size range from 0.05 µm up to 2 µm), using the hydrothermal method, were synthesized. Nanoparticles deposited and dried on a glass surface exhibited bright green upconversion luminescence. By means of an atomic-force microscope, a 60 × 60 µm² square of a glass surface was cleaned from any noticeable contaminants (more than 10 nm in size) and a single particle of 1-µm size was selected and placed in the middle. Confocal microscopy revealed a significant difference between the collective luminescent response of an ensemble of synthesized nanoparticles (in the form of a dry powder) and that of a single particle. In particular, a pronounced polarization of the upconversion luminescence from a single particle was observed. Luminescence dependences on the laser power are quite different for the single particle and the large ensemble of nanoparticles as well. These facts attest to the notion that upconversion properties of single particles are highly individual. This implies that to use an upconversion particle as a single sensor of the local parameters of a medium, the additional studying and calibration of its individual photophysical properties are essential. Full article

(This article belongs to the Special Issue Semiconductors and Nanostructures for Electronics and Photonics)

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17 pages, 8395 KiB

Open AccessArticle

Dual Regime Mode-Locked and Q-Switched Erbium-Doped Fiber Laser by Employing Graphene Filament–Chitin Film-Based Passive Saturable Absorber

by Siti Nur Fatin Zuikafly, Harith Ahmad, Mohd Faizal Ismail, Mohd Azizi Abdul Rahman, Wira Jazair Yahya, Nurulakmar Abu Husain, Khairil Anwar Abu Kassim, Hafizal Yahaya and Fauzan Ahmad

Micromachines 2023, 14(5), 1048; https://doi.org/10.3390/mi14051048 - 14 May 2023

Cited by 2 | Viewed by 1190

Abstract

We investigate the dynamics of high energy dual regime unidirectional Erbium-doped fiber laser in ring cavity, which is passively Q-switched and mode-locked through the use of an environmentally friendly graphene filament–chitin film-based saturable absorber. The graphene–chitin passive saturable absorber allows the option for [...] Read more.

We investigate the dynamics of high energy dual regime unidirectional Erbium-doped fiber laser in ring cavity, which is passively Q-switched and mode-locked through the use of an environmentally friendly graphene filament–chitin film-based saturable absorber. The graphene–chitin passive saturable absorber allows the option for different operating regimes of the laser by simple adjustment of the input pump power, yielding, simultaneously, highly stable and high energy Q-switched pulses at 82.08 nJ and 1.08 ps mode-locked pulses. The finding can have applications in a multitude of fields due to its versatility and the regime of operation that is on demand. Full article

(This article belongs to the Special Issue Semiconductors and Nanostructures for Electronics and Photonics)

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12 pages, 3448 KiB

Open AccessArticle

Laser-Synthesized 2D-MoS₂ Nanostructured Photoconductors

by Igor A. Salimon, Ekaterina V. Zharkova, Aleksandr V. Averchenko, Jatin Kumar, Pavel Somov, Omar A. Abbas, Pavlos G. Lagoudakis and Sakellaris Mailis

Micromachines 2023, 14(5), 1036; https://doi.org/10.3390/mi14051036 - 12 May 2023

Cited by 1 | Viewed by 1571

Abstract

The direct laser synthesis of periodically nanostructured 2D transition metal dichalcogenide (2D-TMD) films, from single source precursors, is presented here. Laser synthesis of MoS₂ and WS₂ tracks is achieved by localized thermal dissociation of Mo and W thiosalts, caused by the [...] Read more.

The direct laser synthesis of periodically nanostructured 2D transition metal dichalcogenide (2D-TMD) films, from single source precursors, is presented here. Laser synthesis of MoS₂ and WS₂ tracks is achieved by localized thermal dissociation of Mo and W thiosalts, caused by the strong absorption of continuous wave (c.w.) visible laser radiation by the precursor film. Moreover, within a range of irradiation conditions we have observed occurrence of 1D and 2D spontaneous periodic modulation in the thickness of the laser-synthesized TMD films, which in some cases is so extreme that it results in the formation of isolated nanoribbons with a width of ~200 nm and a length of several micrometers. The formation of these nanostructures is attributed to the effect that is known as laser-induced periodic surface structures (LIPSS), which is caused by self-organized modulation of the incident laser intensity distribution due to optical feedback from surface roughness. We have fabricated two terminal photoconductive detectors based on nanostructured and continuous films and we show that the nanostructured TMD films exhibit enhanced photo-response, with photocurrent yield increased by three orders of magnitude as compared to their continuous counterparts. Full article

(This article belongs to the Special Issue Semiconductors and Nanostructures for Electronics and Photonics)

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