Two-dimensional (2D) layered materials, including graphene, black phosphorus (BP) and transition metal dichalcogenide (TMD) such as molybdenum disulfide (MoS2), tungsten diselenide (WSe2), have attracted increasing attention for the application in electronic and optoelectronic devices. Contacts, which are the communication links between these 2D materials and external circuitry, have significant effects on the performance of electronic and optoelectronic devices. However, the performance of devices based on 2D semiconductors (SCs) is often limited by the contacts. Here, we provide a comprehensive overview of the basic physics and role of contacts in 2D SCs, elucidating Schottky barrier nature and Fermi level pinning effect at metal/2D SCs contact interface. The progress of contact engineering, including traditional metals contacts and metallic 2D materials contacts, for improving the performance of 2D SCs based devices is presented. Traditional metal contacts, named 3D top and edge contacts, are discussed briefly. Meanwhile, methods of building 2D materials contacts (2D top contact and 2D edge contact) are discussed in detail, such as chemical vapor deposition (CVD) growth of 2D metallic material contacts, phase engineered metallic phase contacts and intercalation induced metallic state contacts. Finally, the challenges and opportunities of contact engineering for 2D SCs are outlined.
J. Semicond. 2020, 41 (7): 071901Peng Zhang, Yiwei Zhang, Yi Wei, Huaning Jiang, Xingguo Wang, Yongji Gong. Contact engineering for two-dimensional semiconductors[J]. Journal of Semiconductors, 2020, 41(7): 071901. doi: 10.1088/1674-4926/41/7/071901.
P Zhang, Y W Zhang, Y Wei, H N Jiang, X G Wang, Y J Gong, Contact engineering for two-dimensional semiconductors[J]. J. Semicond., 2020, 41(7): 071901. doi: 10.1088/1674-4926/41/7/071901.Export: BibTex EndNote
J. Semicond. 2020, 41 (6): 061101Chuen-Keung Sin, Jingzhao Zhang, Kinfai Tse, Junyi Zhu. A brief review of formation energies calculation of surfaces and edges in semiconductors[J]. Journal of Semiconductors, 2020, 41(6): 061101. doi: 10.1088/1674-4926/41/6/061101.
C K Sin, J Z Zhang, K Tse, J Y Zhu, A brief review of formation energies calculation of surfaces and edges in semiconductors[J]. J. Semicond., 2020, 41(6): 061101. doi: 10.1088/1674-4926/41/6/061101.Export: BibTex EndNote
To have a high quality experimental growth of crystals, understanding the equilibrium crystal shape (ECS) in different thermodynamic growth conditions is important. The factor governing the ECS is usually the absolute surface formation energies for surfaces (or edges in 2D) in different orientations. Therefore, it is necessary to obtain an accurate value of these energies in order to give a good explanation for the observation in growth experiment. Historically, there have been different approaches proposed to solve this problem. This paper is going to review these representative literatures and discuss the pitfalls and advantages of different methods.
J. Semicond. 2020, 41 (6): 061401Namrata Mendiratta, Suman Lata Tripathi. A review on performance comparison of advanced MOSFET structures below 45 nm technology node[J]. Journal of Semiconductors, 2020, 41(6): 061401. doi: 10.1088/1674-4926/41/6/061401.
N Mendiratta, S L Tripathi, A review on performance comparison of advanced MOSFET structures below 45 nm technology node[J]. J. Semicond., 2020, 41(6): 061401. doi: 10.1088/1674-4926/41/6/061401.Export: BibTex EndNote
CMOS technology is one of the most frequently used technologies in the semiconductor industry as it can be successfully integrated with ICs. Every two years the number of MOS transistors doubles because the size of the MOSFET is reduced. Reducing the size of the MOSFET reduces the size of the channel length which causes short channel effects and it increases the leakage current. To reduce the short channel effects new designs and technologies are implemented. Double gate MOSFET design has shown improvement in performance as amplifiers over a single MOSFET. Silicon-based MOSFET design can be used in a harsh environment. It has been used in various applications such as in detecting biomolecules. The increase in number of gates increases the current drive capability of transistors. GAA MOSFET is an example of a quadruple gate around the four sides of channel that increases gate control over the channel region. It also increases effective channel width that improves drain current and reduces leakage current keeping short channel effects under limit. Junctionless MOSFET operates faster and uses less power with increase in ON-state current leading to a good value of ION/IOFF ratio. In this paper, several gate and channel engineered MOSFET structures are analyzed and compared for sub 45 nm technology node. A comparison among different MOSFET structures has been made for subthreshold performance parameters in terms of IOFF, subthreshold slope and DIBL values. The analog/RF performance is analyzed for transconductance, effective transistor capacitances, stability factor and critical frequency. The paper also covers different applications of advance MOSFET structures in analog/digital or IoT/ biomedical applications.
J. Semicond. 2020, 41 (5): 051201Yurui Wang, Mei Zhang, Ke Xiao, Renxing Lin, Xin Luo, Qiaolei Han, Hairen Tan. Recent progress in developing efficient monolithic all-perovskite tandem solar cells[J]. Journal of Semiconductors, 2020, 41(5): 051201. doi: 10.1088/1674-4926/41/5/051201.
Y R Wang, M Zhang, K Xiao, R X Lin, X Luo, Q L Han, H R Tan, Recent progress in developing efficient monolithic all-perovskite tandem solar cells[J]. J. Semicond., 2020, 41(5): 051201. doi: 10.1088/1674-4926/41/5/051201.Export: BibTex EndNote
Organic–inorganic halide perovskites have received widespread attention thanks to their strong light absorption, long carrier diffusion lengths, tunable bandgaps, and low temperature processing. Single-junction perovskite solar cells (PSCs) have achieved a boost of the power conversion efficiency (PCE) from 3.8% to 25.2% in just a decade. With the continuous growth of PCE in single-junction PSCs, exploiting of monolithic all-perovskite tandem solar cells is now an important strategy to go beyond the efficiency available in single-junction PSCs. In this review, we first introduce the structure and operation mechanism of monolithic all-perovskite tandem solar cell. We then summarize recent progress in monolithic all-perovskite tandem solar cells from the perspectives of different structural units in the device: tunnel recombination junction, wide-bandgap top subcell, and narrow-bandgap bottom subcell. Finally, we provide our insights into the challenges and scientific issues remaining in this rapidly developing research field.
HI hydrolysis-derived intermediate as booster for CsPbI3 perovskite: from crystal structure, film fabrication to device performance
J. Semicond. 2020, 41 (5): 051202Zhizai Li, Zhiwen Jin. HI hydrolysis-derived intermediate as booster for CsPbI3 perovskite: from crystal structure, film fabrication to device performance[J]. Journal of Semiconductors, 2020, 41(5): 051202. doi: 10.1088/1674-4926/41/5/051202.
Z Z Li, Z W Jin, HI hydrolysis-derived intermediate as booster for CsPbI3 perovskite: from crystal structure, film fabrication to device performance[J]. J. Semicond., 2020, 41(5): 051202. doi: 10.1088/1674-4926/41/5/051202.Export: BibTex EndNote
Nowadays, inorganic CsPbI3 perovskite solar cells (PSCs) have become one of the most attractive research hotspots in photovoltaic field for its superior chemical stability and excellent photo-electronic properties. Since the first independent report in 2015, the power conversion efficiency (PCE) of CsPbI3 based PSCs has sharply increased from 3.9% to 19.03%. Importantly, during the developing process of CsPbI3 PSCs, HI hydrolysis-derived intermediate plays an important role: from stabilizing the crystal structure, optimizing the fabricated film to boosting the device performance. In this review, the different crystal and electronic structures of CsPbI3 are introduced. We then trace the history and disputes of HI hydrolysis-derived intermediate to make this review more logical. Meanwhile, we highlight the functions of HI hydrolysis-derived intermediate, and systematically summarize the advanced works on CsPbI3 PSCs. Finally, the bottlenecks and prospects are revealed to further increase the CsPbI3 PSCs performance.
J. Semicond. 2020, 41 (5): 051203Jianxun Lu, Zhanhua Wei. The strategies for preparing blue perovskite light-emitting diodes[J]. Journal of Semiconductors, 2020, 41(5): 051203. doi: 10.1088/1674-4926/41/5/051203.
J X Lu, Z H Wei, The strategies for preparing blue perovskite light-emitting diodes[J]. J. Semicond., 2020, 41(5): 051203. doi: 10.1088/1674-4926/41/5/051203.Export: BibTex EndNote
Metal halide perovskites have attracted tremendous interest due to their excellent optical and electrical properties, and they find many promising applications in the optoelectronic fields of solar cells, light-emitting diodes, and photodetectors. Thanks to the contributions of international researchers, significant progress has been made for perovskite light-emitting diodes (Pero-LEDs). The external quantum efficiencies (EQEs) of Pero-LEDs with emission of green, red, and near-infrared have all exceeded 20%. However, the blue Pero-LEDs still lag due to the poor film quality and deficient device structure. Herein, we summarize the strategies for preparing blue-emitting perovskites and categorize them into two: compositional engineering and size controlling of the emitting units. The advantages and disadvantages of both strategies are discussed, and a perspective of preparing high-performance blue-emitting perovskite is proposed. The challenges and future directions of blue Pero-LEDs fabrication are also discussed.
J. Semicond. 2020, 41 (5): 051204Yirong Su, Wenbo Ma, Yang (Michael) Yang. Perovskite semiconductors for direct X-ray detection and imaging[J]. Journal of Semiconductors, 2020, 41(5): 051204. doi: 10.1088/1674-4926/41/5/051204.
Y R Su, W B Ma, Y Yang, Perovskite semiconductors for direct X-ray detection and imaging[J]. J. Semicond., 2020, 41(5): 051204. doi: 10.1088/1674-4926/41/5/051204.Export: BibTex EndNote
Halide perovskites have emerged as the next generation of optoelectronic materials and their remarkable performances have been attractive in the fields of solar cells, light-emitting diodes, photodetectors, etc. In addition, halide perovskites have been reported as an attractive new class of X-ray direct detecting materials recently, owning to the strong X-ray stopping capacity, excellent carrier transport, high sensitivity, and cost-effective manufacturing. Meanwhile, perovskite based direct X-ray imagers have been successfully demonstrated as well. In this review article, we firstly introduced some fundamental principles of direct X-ray detection and imaging, and summarized the advances of perovskite materials for these purposes and finally put forward some needful and feasible directions.
J. Semicond. 2020, 41 (5): 051205Gang Cao, Chuantong Cheng, Hengjie Zhang, Huan Zhang, Run Chen, Beiju Huang, Xiaobing Yan, Weihua Pei, Hongda Chen. The application of halide perovskites in memristors[J]. Journal of Semiconductors, 2020, 41(5): 051205. doi: 10.1088/1674-4926/41/5/051205.
G Cao, C T Cheng, H J Zhang, H Zhang, R Chen, B J Huang, X B Yan, W H Pei, H D Chen, The application of halide perovskites in memristors[J]. J. Semicond., 2020, 41(5): 051205. doi: 10.1088/1674-4926/41/5/051205.Export: BibTex EndNote
New neuromorphic architectures and memory technologies with low power consumption, scalability and high-speed are in the spotlight due to the von Neumann bottleneck and limitations of Moore's law. The memristor, a two-terminal synaptic device, shows powerful capabilities in neuromorphic computing and information storage applications. Active materials with high defect migration speed and low defect migration barrier are highly promising for high-performance memristors. Halide perovskite (HP) materials with point defects (such as gaps, vacancies, and inversions) have strong application potential in memristors. In this article, we review recent advances on HP memristors with exceptional performances. First, the working mechanisms of memristors are described. Then, the structures and properties of HPs are explained. Both electrical and photonic HP-based memristors are overviewed and discussed. Different fabrication methods of HP memristor devices and arrays are described and compared. Finally, the challenges in integrating HP memristors with complementary metal oxide semiconductors (CMOS) are briefly discussed. This review can assist in developing HP memristors for the next-generation information technology.
J. Semicond. 2020, 41 (4): 041601Zhong Ma, Desheng Kong, Lijia Pan, Zhenan Bao. Skin-inspired electronics: emerging semiconductor devices and systems[J]. Journal of Semiconductors, 2020, 41(4): 041601. doi: 10.1088/1674-4926/41/4/041601.
Z Ma, D S Kong, L J Pan, Z N Bao, Skin-inspired electronics: emerging semiconductor devices and systems[J]. J. Semicond., 2020, 41(4): 041601. doi: 10.1088/1674-4926/41/4/041601.Export: BibTex EndNote
Current electronics are driven by advanced microfabrication for fast and efficient information processing. In spite of high performance, these wafer-based devices are rigid, non-degradable, and unable to autonomous repair. Skin-inspired electronics have emerged as a new class of devices and systems for next-generation flexible and wearable electronics. The technology gains inspiration from the structures, properties, and sensing mechanisms of the skin, which may find a broad range of applications in cutting-edge fields such as healthcare monitoring, human-machine interface, and soft robotics/prostheses. Practical demands have fueled the development of electronic materials with skin-like properties in terms of stretchability, self-healing capability, and biodegradability. These materials provide the basis for functional sensors with innovative and biomimetic designs. Further system-level integrations and optimizations enable new forms of electronics for real-world applications. This review summarizes recent advancements in this active area and speculates on future directions.
J. Semicond. 2020, 41 (4): 041602Tianyao Zhang, Guang Yao, Taisong Pan, Qingjian Lu, Yuan Lin. Flexible inorganic oxide thin-film electronics enabled by advanced strategies[J]. Journal of Semiconductors, 2020, 41(4): 041602. doi: 10.1088/1674-4926/41/4/041602.
T Y Zhang, G Yao, T S Pan, Q J Lu, Y Lin, Flexible inorganic oxide thin-film electronics enabled by advanced strategies[J]. J. Semicond., 2020, 41(4): 041602. doi: 10.1088/1674-4926/41/4/041602.Export: BibTex EndNote
With the advent of human-friendly intelligent life, as well as increasing demands for natural and seamless human-machine interactions, flexibility and wearability are among the inevitable development trends for electronic devices in the future. Due to the advantages of rich physicochemical properties, flexible and stretchable inorganic oxide thin-film electronics play an increasingly important role in the emerging and exciting flexible electronic field, and they will act as a critical player in next-generation electronics. However, a stable strategy to render flexibility while maintaining excellent performance of oxide thin films is the most demanding and challenging problem, both for academic and industrial communities. Thus, this review focuses on the latest advanced strategies to achieve flexible inorganic oxide thin-film electronics. This review emphasizes the physical transferring strategies that are based on mechanical peeling and the chemical transferring strategies that are based on sacrificial layer etching. Finally, this review evaluates and summarizes the merits and demerits of these strategies toward actual applications, concluding with a future perspective into the challenges and opportunities for the next-generation of flexible inorganic oxide thin-film electronics.
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