A practical strategy is proposed to facilitate the migration of holes in semiconductor (the low rate of which limits photocatalytic efficiency) by taking advantage of the Schottky barrier between ...p‐type semiconductor and metal. A high work function is found to serve as an important selection rule for building such desirable Schottky junction between semiconductor surface facets and metal. The intrinsic charge spatial distribution has to be taken into account when selecting the facets, as it results in accumulation of photoexcited electrons and holes on certain semiconductor facets. Importantly, the facets have a high work function, the same characteristic required for the formation of Schottky junction in a p‐type semiconductor–metal hybrid structure. As a result, the semiconductor crystals in the hybrid design may be better enclosed by single facets with high work function, so as to synergize the two effects: Schottky barrier versus charge spatial separation.
Surface facets matter: Palladium‐decorated Cu2O microcrystals exhibit a capability of producing hydrogen from pure water under visible irradiation with well‐designed surface facets. This feat is otherwise hard to attain by other Cu2O‐based counterparts.
In this work, we analyze the impact of random dopant fluctuations (RDFs) on the mismatch behavior of the negative capacitance field-effect transistor (NCFET). We observe that the drain current ...mismatch decreases in the NCFET compared to conventional MOSFET, and it further decreases with an increase in the thickness of the ferroelectric layer (<inline-formula> <tex-math notation="LaTeX">{t}_{\text {fe}} </tex-math></inline-formula>). Metal-ferroelectric-metal-insulator-semiconductor (MFMIS)-type NCFET shows 24% and 22% improvement in mismatch power in comparison to baseline FET at <inline-formula> <tex-math notation="LaTeX">\vert {V}_{\text {GS}}\vert = {0.2} </tex-math></inline-formula> and 1 V, respectively. We show that the mismatch in NCFET is directly proportional to channel doping concentration, similar to baseline MOSFET. For the first time, we demonstrate that mismatch power varies nonmonotonically with the variation in the Landau coefficient <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula>, and the other Landau coefficient <inline-formula> <tex-math notation="LaTeX">\beta </tex-math></inline-formula> has an impact on mismatch at higher <inline-formula> <tex-math notation="LaTeX">{t}_{\text {fe}} </tex-math></inline-formula> only. We also present a compact model, under the industry standard Berkeley Short-channel IGFET Model for Bulk MOSFET (BSIM-BULK) MOS model's framework, which can accurately capture drain current mismatch from subthreshold to strong inversion region for NCFET. The model is extensively validated with the experimentally calibrated technology computer-aided design (TCAD) simulations across different biases and temperatures.
Stretchable polymer semiconductors have advanced rapidly in the past decade as materials required to realize conformable and soft skin-like electronics become available. Through rational ...molecular-level design, stretchable polymer semiconductor films are now able to retain their electrical functionalities even when subjected to repeated mechanical deformations. Furthermore, their charge-carrier mobilities are on par with the best flexible polymer semiconductors, with some even exceeding that of amorphous silicon. The key advancements are molecular-design concepts that allow multiple strain energy-dissipation mechanisms, while maintaining efficient charge-transport pathways over multiple length scales. In this perspective article, we review recent approaches to confer stretchability to polymer semiconductors while maintaining high charge carrier mobilities, with emphasis on the control of both polymer-chain dynamics and thin-film morphology. Additionally, we present molecular design considerations toward intrinsically elastic semiconductors that are needed for reliable device operation under reversible and repeated deformation. A general approach involving inducing polymer semiconductor nanoconfinement allows for incorporation of several other desired functionalities, such as biodegradability, self-healing, and photopatternability, while enhancing the charge transport. Lastly, we point out future directions, including advancing the fundamental understanding of morphology evolution and its correlation with the change of charge transport under strain, and needs for strain-resilient polymer semiconductors with high mobility retention.
In this paper, the impact of nanowire source/drain extension, diameter, and channel length on nanowire (NW) device performance is investigated. We present a novel approach using the extension length ...as tuning parameter to match the drive current of n- and p-FET in NW CMOS logic applicable down to 10-nm gate length. Our approach overcomes the drive matching issue in NW/FinFET based CMOS circuits. We show that, in comparison to conventional CMOS, where the number of NWs/fins in p-FET is used to match n-FET drive, the proposed approach provides a significant reduction in circuit active area and power dissipation. When compared to conventional CMOS inverter, the proposed approach shows 20% lower area, and 35% saving in power in case of NW CMOS inverter. Our results show that extension length tuned-CMOS has an excellent option for low-power applications in both NW and FinFET technologies.
A fourth-order continuous-time RF bandpass Formula Omitted ADC has been fabricated in 40 nm CMOS for Formula Omitted operation around a 2.22 GHz central frequency. A complete system has been ...implemented on the test chip including the ADC core, the fractional-N PLL with clock generation network, and the digital decimation filters and downconversion (DFD). The quantizers of the ADC are six times interleaved enabling a polyphase structure for the DFD and relaxing clock frequency requirements. This quantization scheme realizes a sampling rate of 8.88 GS/s which is the highest sampling speed for RF bandpass Formula Omitted ADCs reported in standard CMOS to date enabling high oversampling ratios for RF digitization without compromising power-efficient implementation of the DFD. Measurements show that the ADC achieves a dynamic range of 48 dB in a band of 80 MHz with an IIPFormula Omitted of 1 dBm.
This article is written from an organic chemist’s point of view and provides an up‐to‐date review about organic solar cells based on small molecules or oligomers as absorbers and in detail deals with ...devices that incorporate planar‐heterojunctions (PHJ) and bulk heterojunctions (BHJ) between a donor (p‐type semiconductor) and an acceptor (n‐type semiconductor) material. The article pays particular attention to the design and development of molecular materials and their performance in corresponding devices. In recent years, a substantial amount of both, academic and industrial research, has been directed towards organic solar cells, in an effort to develop new materials and to improve their tunability, processability, power conversion efficiency, and stability. On the eve of commercialization of organic solar cells, this review provides an overview over efficiencies attained with small molecules/oligomers in OSCs and reflects materials and device concepts developed over the last decade. Approaches to enhancing the efficiency of organic solar cells are analyzed.
Energy from molecules: Solar cells incorporating small molecules and oligomers as light‐absorbing materials are presented in this Review, in which structure–property–efficiency correlations are discussed for a vast number of organic semiconducting materials. These properties should help in the design of new and highly efficient materials.
Bi-based semiconductor materials have special layered structure and appropriate band gap, which endow them with excellent visible light response ability and stable photochemical characteristics. As a ...new type of environment-friendly photocatalyst, they have received extensive attention in the fields of environmental remediation and energy crisis resolution and have become a research hotspot in recent years. However, there are still some urgent issues that need to be addressed in the practical large-scale application of Bi-based photocatalysts, such as the high recombination rate of photogenerated carriers, limited response range to visible spectra, poor photocatalytic activity, and weak reduction ability. In this paper, the reaction conditions and mechanism of photocatalytic reduction of COsub.2 and the typical characteristics of Bi-based semiconductor materials are introduced. On this basis, the research progress and application results of Bi-based photocatalysts in the field of reducing COsub.2, including vacancy introduction, morphological control, heterojunction construction, and co-catalyst loading, are emphasized. Finally, the future prospects of Bi-based photocatalysts are prospected, and it is pointed out that future research directions should be focused on improving the selectivity and stability of catalysts, deeply exploring reaction mechanisms, and meeting industrial production requirements.
Optical and photoelectric measurements reveal that doping with iron leads to the formation of a deep level at E.sub.c--0.69 eV in Hg.sub.3In.sub.2Te.sub.6 crystals. When light is absorbed by ...Fe.sup.2+ impurity centers, both electronic transitions of the impurity-level-conduction-band type and optical transitions between ground and excited states of the aforementioned centers (intracenter transitions) are observed. Investigations of transport phenomena point to the acceptor properties of Fe.sup.2+ centers. DOI: 10.1134/S106378261507009X
This book has been designed as a result of the author s teaching experiences; students in the courses came from various disciplines and it was very difficult to prescribe a suitable textbook, not ...because there are no books on these topics, but because they are either too exhaustive or very elementary. This book, therefore, includes only relevant topics in the fundamentals of the physics of semiconductors and of electrochemistry needed for understanding the intricacy of the subject of photovoltaic solar cells and photoelectrochemical (PEC) solar cells. The book provides the basic concepts of semiconductors, p:n junctions, PEC solar cells, electrochemistry of semiconductors, and photochromism. Researchers, engineers and students engaged in researching/teaching PEC cells or knowledge of our sun, its energy, and its distribution to the earth will find essential topics such as the physics of semiconductors, the electrochemistry of semiconductors, p:n junctions, Schottky junctions, the concept of Fermi energy, and photochromism and its industrial applications. The topics in this book are explained with clear illustration and indispensable terminology. It covers both fundamental and advanced topics in photoelectrochemistry and I believe that the content presented in this monograph will be a resource in the development of both academic and industrial research . Professor Akira Fujishima, President, Tokyo University of Science, and Director, Photocatalysis International Research Center, Tokyo University of Science, Japan
