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11 pages, 3014 KiB

Open AccessEditor’s ChoiceArticle

Silicon-Carbide (SiC) Nanocrystal Technology and Characterization and Its Applications in Memory Structures

by Andrzej Mazurak, Robert Mroczyński, David Beke and Adam Gali

Nanomaterials 2020, 10(12), 2387; https://doi.org/10.3390/nano10122387 - 29 Nov 2020

Cited by 9 | Viewed by 3413

Abstract

Colloidal cubic silicon-carbide nanocrystals have been fabricated, characterized, and introduced into metal–insulator–semiconductor and metal–insulator–metal structures based on hafnium oxide layers. The fabricated structures were characterized through the stress-and-sense measurements in terms of device capacitance, flat-band voltage shift, switching characteristics, and retention time. The [...] Read more.

Colloidal cubic silicon-carbide nanocrystals have been fabricated, characterized, and introduced into metal–insulator–semiconductor and metal–insulator–metal structures based on hafnium oxide layers. The fabricated structures were characterized through the stress-and-sense measurements in terms of device capacitance, flat-band voltage shift, switching characteristics, and retention time. The examined electrical performance of the sample structures has demonstrated the feasibility of the application of both types of structures based on SiC nanoparticles in memory devices. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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12 pages, 7653 KiB

Open AccessArticle

Strained Si_0.2Ge_0.8/Ge multilayer Stacks Epitaxially Grown on a Low-/High-Temperature Ge Buffer Layer and Selective Wet-Etching of Germanium

by Lu Xie, Huilong Zhu, Yongkui Zhang, Xuezheng Ai, Guilei Wang, Junjie Li, Anyan Du, Zhenzhen Kong, Xiaogen Yin, Chen Li, Liheng Zhao, Yangyang Li, Kunpeng Jia, Ben Li and Henry H. Radamson

Nanomaterials 2020, 10(9), 1715; https://doi.org/10.3390/nano10091715 - 29 Aug 2020

Cited by 6 | Viewed by 3864

Abstract

With the development of new designs and materials for nano-scale transistors, vertical Gate-All-Around Field Effect Transistors (vGAAFETs) with germanium as channel materials have emerged as excellent choices. The driving forces for this choice are the full control of the short channel effect and [...] Read more.

With the development of new designs and materials for nano-scale transistors, vertical Gate-All-Around Field Effect Transistors (vGAAFETs) with germanium as channel materials have emerged as excellent choices. The driving forces for this choice are the full control of the short channel effect and the high carrier mobility in the channel region. In this work, a novel process to form the structure for a VGAA transistor with a Ge channel is presented. The structure consists of multilayers of Si_0.2Ge_0.8/Ge grown on a Ge buffer layer grown by the reduced pressure chemical vapor deposition technique. The Ge buffer layer growth consists of low-temperature growth at 400 °C and high-temperature growth at 650 °C. The impact of the epitaxial quality of the Ge buffer on the defect density in the Si_0.2Ge_0.8/Ge stack has been studied. In this part, different thicknesses (0.6, 1.2 and 2.0 µm) of the Ge buffer on the quality of the Si_0.2Ge_0.8/Ge stack structure have been investigated. The thicker Ge buffer layer can improve surface roughness. A high-quality and atomically smooth surface with RMS 0.73 nm of the Si_0.2Ge_0.8/Ge stack structure can be successfully realized on the 1.2 µm Ge buffer layer. After the epitaxy step, the multilayer is vertically dry-etched to form a fin where the Ge channel is selectively released to SiGe by using wet-etching in HNO₃ and H₂O₂ solution at room temperature. It has been found that the solution concentration has a great effect on the etch rate. The relative etching depth of Ge is linearly dependent on the etching time in H₂O₂ solution. The results of this study emphasize the selective etching of germanium and provide the experimental basis for the release of germanium channels in the future. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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15 pages, 8212 KiB

Open AccessArticle

Effects of 5 MeV Proton Irradiation on Nitrided SiO₂/4H-SiC MOS Capacitors and the Related Mechanisms

by Dongxun Li, Yuming Zhang, Xiaoyan Tang, Yanjing He, Hao Yuan, Yifan Jia, Qingwen Song, Ming Zhang and Yimen Zhang

Nanomaterials 2020, 10(7), 1332; https://doi.org/10.3390/nano10071332 - 8 Jul 2020

Cited by 6 | Viewed by 2580

Abstract

In this paper the effects of 5 MeV proton irradiation on nitrided SiO₂/4H-SiC metal–oxide–semiconductor (MOS) capacitors are studied in detail and the related mechanisms are revealed. The density of interface states (Dit) is increased with the irradiation doses, and the annealing [...] Read more.

In this paper the effects of 5 MeV proton irradiation on nitrided SiO₂/4H-SiC metal–oxide–semiconductor (MOS) capacitors are studied in detail and the related mechanisms are revealed. The density of interface states (Dit) is increased with the irradiation doses, and the annealing response suggests that the worse of Dit is mainly caused by displacement effect of proton irradiation. However, the X-rays photoelectron spectroscopy (XPS) measurement shows that the quantity proportion of breaking of Si≡N induced by displacement is only 8%, which means that the numbers of near interface electron traps (NIETs) and near interface hole traps (NIHTs) are not significantly changed by the displacement effect. The measurements of bidirectional high frequency (HF) C-V characteristics and positive bias stress stability show that the number of un-trapped NIETs and oxide electron traps decreased with increasing irradiation doses because they are filled by electrons resulted from the ionization effect of proton irradiation, benefiting to the field effective mobility (μ_FE) and threshold voltage stability of metal–oxide–semiconductor field-effect transistors (MOSFETs). The obviously negative shift of flat-band voltage (V_FB) resulted from the dominant NIHTs induced by nitrogen passivation capture more holes produced by ionization effect, which has been revealed by the experimental samples with different nitrogen content under same irradiation dose. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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11 pages, 2388 KiB

Open AccessFeature PaperArticle

CMOS-Compatible and Low-Cost Thin Film MACE Approach for Light-Emitting Si NWs Fabrication

by Antonio Alessio Leonardi, Maria José Lo Faro and Alessia Irrera

Nanomaterials 2020, 10(5), 966; https://doi.org/10.3390/nano10050966 - 18 May 2020

Cited by 20 | Viewed by 3462

Abstract

Silicon nanowires (Si NWs) are emerging as an innovative building block in several fields, such as microelectronics, energetics, photonics, and sensing. The interest in Si NWs is related to the high surface to volume ratio and the simpler coupling with the industrial flat [...] Read more.

Silicon nanowires (Si NWs) are emerging as an innovative building block in several fields, such as microelectronics, energetics, photonics, and sensing. The interest in Si NWs is related to the high surface to volume ratio and the simpler coupling with the industrial flat architecture. In particular, Si NWs emerge as a very promising material to couple the light to silicon. However, with the standard synthesis methods, the realization of quantum-confined Si NWs is very complex and often requires expensive equipment. Metal-Assisted Chemical Etching (MACE) is gaining more and more attention as a novel approach able to guarantee high-quality Si NWs and high density with a cost-effective approach. Our group has recently modified the traditional MACE approach through the use of thin metal films, obtaining a strong control on the optical and structural properties of the Si NWs as a function of the etching process. This method is Complementary Metal-Oxide-Semiconductors (CMOS)-technology compatible, low-cost, and permits us to obtain a high density, and room temperature light-emitting Si NWs due to the quantum confinement effect. A strong control on the Si NWs characteristics may pave the way to a real industrial transfer of this fabrication methodology for both microelectronics and optoelectronics applications. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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12 pages, 1805 KiB

Open AccessArticle

Formation of Thin NiGe Films by Magnetron Sputtering and Flash Lamp Annealing

by Viktor Begeza, Erik Mehner, Hartmut Stöcker, Yufang Xie, Alejandro García, Rene Hübner, Denise Erb, Shengqiang Zhou and Lars Rebohle

Nanomaterials 2020, 10(4), 648; https://doi.org/10.3390/nano10040648 - 31 Mar 2020

Cited by 5 | Viewed by 3230

Abstract

The nickel monogermanide (NiGe) phase is known for its electrical properties such as low ohmic and low contact resistance in group-IV-based electronics. In this work, thin films of nickel germanides (Ni–Ge) were formed by magnetron sputtering followed by flash lamp annealing (FLA). The [...] Read more.

The nickel monogermanide (NiGe) phase is known for its electrical properties such as low ohmic and low contact resistance in group-IV-based electronics. In this work, thin films of nickel germanides (Ni–Ge) were formed by magnetron sputtering followed by flash lamp annealing (FLA). The formation of NiGe was investigated on three types of substrates: on amorphous (a-Ge) as well as polycrystalline Ge (poly-Ge) and on monocrystalline (100)-Ge (c-Ge) wafers. Substrate and NiGe structure characterization was performed by Raman, TEM, and XRD analyses. Hall Effect and four-point-probe measurements were used to characterize the films electrically. NiGe layers were successfully formed on different Ge substrates using 3-ms FLA. Electrical as well as XRD and TEM measurements are revealing the formation of Ni-rich hexagonal and cubic phases at lower temperatures accompanied by the formation of the low-resistivity orthorhombic NiGe phase. At higher annealing temperatures, Ni-rich phases are transforming into NiGe, as long as the supply of Ge is ensured. NiGe layer formation on a-Ge is accompanied by metal-induced crystallization and its elevated electrical resistivity compared with that of poly-Ge and c-Ge substrates. Specific resistivities for 30 nm Ni on Ge were determined to be 13.5 μΩ·cm for poly-Ge, 14.6 μΩ·cm for c-Ge, and 20.1 μΩ·cm for a-Ge. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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18 pages, 4148 KiB

Open AccessFeature PaperArticle

Gold Nanoparticles Synthesis Using Stainless Steel as Solid Reductant: A Critical Overview

by Margherita Izzi, Maria C. Sportelli, Luciana Tursellino, Gerardo Palazzo, Rosaria A. Picca, Nicola Cioffi and Ángela I. López Lorente

Nanomaterials 2020, 10(4), 622; https://doi.org/10.3390/nano10040622 - 27 Mar 2020

Cited by 5 | Viewed by 3714

Abstract

Gold nanoparticles (AuNPs) were produced using stainless steel as a solid reductant to assist the synthesis of metal NPs, using HAuCl₄ as a precursor. This method is very easy, quick, and cost-effective, allowing the synthesis of highly stable NPs without additional capping [...] Read more.

Gold nanoparticles (AuNPs) were produced using stainless steel as a solid reductant to assist the synthesis of metal NPs, using HAuCl₄ as a precursor. This method is very easy, quick, and cost-effective, allowing the synthesis of highly stable NPs without additional capping agents. However, the reaction mechanism is still under debate. In order to contribute to the investigation of the synthesis of AuNPs using stainless steel, different experimental conditions were tested. Cl⁻ concentration, pH of the precursor solution, as well as stainless steel composition were systematically changed. The syntheses were performed recording the open circuit potential to potentiometrically explore the electrochemical properties of the system, under operando conditions. Spectroscopic and morphological characterizations were carried out along with potentiometric monitoring, aiming at correlating the synthesis parameters with the AuNPs characteristics. As a result, an overview of the process features, and of its most reasonable mechanism were obtained. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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11 pages, 2730 KiB

Open AccessArticle

Bright Single-Photon Emitting Diodes Based on the Silicon-Vacancy Center in AlN/Diamond Heterostructures

by Igor A. Khramtsov and Dmitry Yu. Fedyanin

Nanomaterials 2020, 10(2), 361; https://doi.org/10.3390/nano10020361 - 19 Feb 2020

Cited by 13 | Viewed by 3798

Abstract

Practical implementation of many quantum information and sensing technologies relies on the ability to efficiently generate and manipulate single-photon photons under ambient conditions. Color centers in diamond, such as the silicon-vacancy (SiV) center, have recently emerged as extremely attractive single-photon emitters for room [...] Read more.

Practical implementation of many quantum information and sensing technologies relies on the ability to efficiently generate and manipulate single-photon photons under ambient conditions. Color centers in diamond, such as the silicon-vacancy (SiV) center, have recently emerged as extremely attractive single-photon emitters for room temperature applications. However, diamond is a material at the interface between insulators and semiconductors. Therefore, it is extremely difficult to excite color centers electrically and consequently develop bright and efficient electrically driven single-photon sources. Here, using a comprehensive theoretical approach, we propose and numerically demonstrate a concept of a single-photon emitting diode (SPED) based on a SiV center in a nanoscale AlN/diamond heterojunction device. We find that in spite of the high potential barrier for electrons in AlN at the AlN/diamond heterojunction, under forward bias, electrons can be efficiently injected from AlN into the i-type diamond region of the n-AlN/i-diamond/p-diamond heterostructure, which ensures bright single-photon electroluminescence (SPEL) of the SiV center located in the i-type diamond region. The maximum SPEL rate is more than five times higher than what can be achieved in SPEDs based on diamond p-i-n diodes. Despite the high density of defects at the AlN/diamond interface, the SPEL rate can reach about 4 Mcps, which coincides with the limit imposed by the quantum efficiency and the lifetime of the shelving state of the SiV center. These findings provide new insights into the development of bright room-temperature electrically driven single-photon sources for quantum information technologies and, we believe, stimulate further research in this area. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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15 pages, 4412 KiB

Open AccessFeature PaperArticle

Fractal Silver Dendrites as 3D SERS Platform for Highly Sensitive Detection of Biomolecules in Hydration Conditions

by Maria José Lo Faro, Cristiano D’Andrea, Antonio Alessio Leonardi, Dario Morganti, Alessia Irrera and Barbara Fazio

Nanomaterials 2019, 9(11), 1630; https://doi.org/10.3390/nano9111630 - 16 Nov 2019

Cited by 30 | Viewed by 4591

Abstract

In this paper, we report on the realization of a highly sensitive and low cost 3D surface-enhanced Raman scattering (SERS) platform. The structural features of the Ag dendrite network that characterize the SERS material were exploited, attesting a remarked self-similarity and scale invariance [...] Read more.

In this paper, we report on the realization of a highly sensitive and low cost 3D surface-enhanced Raman scattering (SERS) platform. The structural features of the Ag dendrite network that characterize the SERS material were exploited, attesting a remarked self-similarity and scale invariance over a broad range of length scales that are typical of fractal systems. Additional structural and optical investigations confirmed the purity of the metal network, which was characterized by low oxygen contamination and by broad optical resonances introduced by the fractal behavior. The SERS performances of the 3D fractal Ag dendrites were tested for the detection of lysozyme as probe molecule, attesting an enhancement factor of ~2.4 × 10⁶. Experimental results assessed the dendrite material as a suitable SERS detection platform for biomolecules investigations in hydration conditions. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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11 pages, 3717 KiB

Open AccessArticle

Electrodeposition of Nanoparticles and Continuous Film of CdSe on n-Si (100)

by Walter Giurlani, Vincenzo Dell’Aquila, Martina Vizza, Nicola Calisi, Alessandro Lavacchi, Alessia Irrera, Maria Josè Lo Faro, Antonio Alessio Leonardi, Dario Morganti and Massimo Innocenti

Nanomaterials 2019, 9(10), 1504; https://doi.org/10.3390/nano9101504 - 22 Oct 2019

Cited by 17 | Viewed by 3818

Abstract

CdSe electrodeposition on n-Si (100) substrate was investigated in sulfuric acid solution. The behaviour and the deposition of the precursors (Cd and Se) were studied separately at first. Then, we explored both the alternated deposition, one layer by one, as well as the [...] Read more.

CdSe electrodeposition on n-Si (100) substrate was investigated in sulfuric acid solution. The behaviour and the deposition of the precursors (Cd and Se) were studied separately at first. Then, we explored both the alternated deposition, one layer by one, as well as the simultaneous co-deposition of the two elements to form the CdSe semiconductor. Varying the deposition conditions, we were able to obtain nanoparticles, or a thin film, on the surface of the electrode. The samples were then characterised microscopically and spectroscopically with SEM, XRD and XPS. Finally, we evaluated the induced photoemission of the deposit for the application in optoelectronics. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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17 pages, 2855 KiB

Open AccessArticle

Effect of TiO₂-ZnO-MgO Mixed Oxide on Microbial Growth and Toxicity against Artemia salina

by Luis M. Anaya-Esparza, Napoleón González-Silva, Elhadi M. Yahia, O. A. González-Vargas, Efigenia Montalvo-González and Alejandro Pérez-Larios

Nanomaterials 2019, 9(7), 992; https://doi.org/10.3390/nano9070992 - 10 Jul 2019

Cited by 28 | Viewed by 4524

Abstract

Mixed oxide nanoparticles (MONs, TiO₂–ZnO–MgO) obtained by the sol-gel method were characterized by transmission electron microscopy, (TEM, HRTEM, and SAED) and thermogravimetric analysis (TGA/DTGA–DTA). Furthermore, the effect of MONs on microbial growth (growth profiling curve, lethal and sublethal effect) of Escherichia [...] Read more.

Mixed oxide nanoparticles (MONs, TiO₂–ZnO–MgO) obtained by the sol-gel method were characterized by transmission electron microscopy, (TEM, HRTEM, and SAED) and thermogravimetric analysis (TGA/DTGA–DTA). Furthermore, the effect of MONs on microbial growth (growth profiling curve, lethal and sublethal effect) of Escherichia coli, Salmonella paratyphi, Staphylococcus aureus and Listeria monocytogenes, as well as the toxicity against Artemia salina by the lethal concentration test (LC₅₀) were evaluated. MONs exhibited a near-spherical in shape, polycrystalline structure and mean sizes from 17 to 23 nm. The thermal analysis revealed that the anatase phase of MONs is completed around 480–500 °C. The normal growth of all bacteria tested is affected by the MONs presence compared with the control group. MONs also exhibited a reduction on the plate count from 0.58 to 2.10 log CFU/mL with a sublethal cell injury from 17 to 98%. No significant toxicity within 24 h was observed on A. salina. A bacteriostatic effect of MONs on bacteria was evidenced, which was strongly influenced by the type of bacteria, as well as no toxic effects (LC₅₀ >1000 mg/L; TiO₂–ZnO (5%)–MgO (5%)) on A. salina were detected. This study demonstrates the potential of MONs for industrial applications. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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13 pages, 2997 KiB

Open AccessArticle

Study on the Physico-Chemical Properties of the Si Nanowires Surface

by Rosaria A. Puglisi, Corrado Bongiorno, Giovanni Borgh, Enza Fazio, Cristina Garozzo, Giovanni Mannino, Fortunato Neri, Giovanna Pellegrino, Silvia Scalese and Antonino La Magna

Nanomaterials 2019, 9(6), 818; https://doi.org/10.3390/nano9060818 - 30 May 2019

Cited by 9 | Viewed by 3823

Abstract

Silicon nanowires (Si-NWs) have been extensively studied for their numerous applications in nano-electronics. The most common method for their synthesis is the vapor–liquid–solid growth, using gold as catalyst. After the growth, the metal remains on the Si-NW tip, representing an important issue, because [...] Read more.

Silicon nanowires (Si-NWs) have been extensively studied for their numerous applications in nano-electronics. The most common method for their synthesis is the vapor–liquid–solid growth, using gold as catalyst. After the growth, the metal remains on the Si-NW tip, representing an important issue, because Au creates deep traps in the Si band gap that deteriorate the device performance. The methods proposed so far to remove Au offer low efficiency, strongly oxidize the Si-NW sidewalls, or produce structural damage. A physical and chemical characterization of the as-grown Si-NWs is presented. A thin shell covering the Au tip and acting as a barrier is found. The chemical composition of this layer is investigated through high resolution transmission electron microscopy (TEM) coupled with chemical analysis; its formation mechanism is discussed in terms of atomic interdiffusion phenomena, driven by the heating/cooling processes taking place inside the eutectic-Si-NW system. Based on the knowledge acquired, a new efficient etching procedure is developed. The characterization after the chemical etching is also performed to monitor the removal process and the Si-NWs morphological characteristics, demonstrating the efficiency of the proposed method and the absence of modifications in the nanostructure. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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Review

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54 pages, 22017 KiB

Open AccessReview

Silicon Nanowires for Gas Sensing: A Review

by Mehdi Akbari-Saatlu, Marcin Procek, Claes Mattsson, Göran Thungström, Hans-Erik Nilsson, Wenjuan Xiong, Buqing Xu, You Li and Henry H. Radamson

Nanomaterials 2020, 10(11), 2215; https://doi.org/10.3390/nano10112215 - 6 Nov 2020

Cited by 98 | Viewed by 8554

Abstract

The unique electronic properties of semiconductor nanowires, in particular silicon nanowires (SiNWs), are attractive for the label-free, real-time, and sensitive detection of various gases. Therefore, over the past two decades, extensive efforts have been made to study the gas sensing function of NWs. [...] Read more.

The unique electronic properties of semiconductor nanowires, in particular silicon nanowires (SiNWs), are attractive for the label-free, real-time, and sensitive detection of various gases. Therefore, over the past two decades, extensive efforts have been made to study the gas sensing function of NWs. This review article presents the recent developments related to the applications of SiNWs for gas sensing. The content begins with the two basic synthesis approaches (top-down and bottom-up) whereby the advantages and disadvantages of each approach have been discussed. Afterwards, the basic sensing mechanism of SiNWs for both resistor and field effect transistor designs have been briefly described whereby the sensitivity and selectivity to gases after different functionalization methods have been further presented. In the final words, the challenges and future opportunities of SiNWs for gas sensing have been discussed. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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86 pages, 27947 KiB

Open AccessReview

State of the Art and Future Perspectives in Advanced CMOS Technology

by Henry H. Radamson, Huilong Zhu, Zhenhua Wu, Xiaobin He, Hongxiao Lin, Jinbiao Liu, Jinjuan Xiang, Zhenzhen Kong, Wenjuan Xiong, Junjie Li, Hushan Cui, Jianfeng Gao, Hong Yang, Yong Du, Buqing Xu, Ben Li, Xuewei Zhao, Jiahan Yu, Yan Dong and Guilei Wang

Nanomaterials 2020, 10(8), 1555; https://doi.org/10.3390/nano10081555 - 7 Aug 2020

Cited by 136 | Viewed by 22733

Abstract

The international technology roadmap of semiconductors (ITRS) is approaching the historical end point and we observe that the semiconductor industry is driving complementary metal oxide semiconductor (CMOS) further towards unknown zones. Today’s transistors with 3D structure and integrated advanced strain engineering differ radically [...] Read more.

The international technology roadmap of semiconductors (ITRS) is approaching the historical end point and we observe that the semiconductor industry is driving complementary metal oxide semiconductor (CMOS) further towards unknown zones. Today’s transistors with 3D structure and integrated advanced strain engineering differ radically from the original planar 2D ones due to the scaling down of the gate and source/drain regions according to Moore’s law. This article presents a review of new architectures, simulation methods, and process technology for nano-scale transistors on the approach to the end of ITRS technology. The discussions cover innovative methods, challenges and difficulties in device processing, as well as new metrology techniques that may appear in the near future. Full article

(This article belongs to the Special Issue Nanomaterials Based on IV-Group Semiconductors)

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