Inkjet-Printed MoS2 Transistors with Predominantly Intraflake Transport.

2D semiconductors, such as transition metal dichalcogenides (TMDs) show a rare combination of physical properties that include a large-enough bandgap to ensure sufficient current modulation in transistors, matching electron and hole mobility for complimentary logic operation, and sufficient mechanical flexibility of the nanosheets. Moreover, the solvent-exfoliated TMD-nanosheets may also be processed at low temperatures and onto a wide variety of substrates. However, the poor inter-flake transport in solution-cast 2D-TMD network transistors hinders the realization of high device mobility and current modulations that the intraflake transistors can regularly demonstrate. In this regard, fully printed and electrolyte-gated, narrow-channel MoS2 field-effect transistors (FETs) with simultaneous high current saturation (>310 µA µm-1 ) and on-off ratio (>106 ) are proposed here. The transport limitation is overcome by printing an additional metal layer onto the 2D-TMD nanosheet channel, which substantially shortens the effective channel lengths and results in predominant intraflake transport. In addition, a channel-capacitance-modulation induced subthermionic transport is recorded, which leads to a subthreshold slope value as low as 7.5 mV dec-1 . On the other hand, thermionic MOSFETs and fully printed depletion-mode NMOS inverters are also presented. The demonstrated generic approach involving chemically exfoliated nanosheet inks and the absolute device yield indicates the feasibility of fully printed 2D-TMD electronics.

Mobile apps for SME business sustainability during COVID-19 and onwards.

Small and Medium-Sized Enterprises (SMEs) are struggling to cope with the business uncertainty caused by the COVID-19 pandemic. This study examines how SMEs in developing economies have used mobile apps to improve their business efficiency during the pandemic. We aim to recognize effective measures and actions taken by SMEs that have turned to mobile-app-based business to improve their sustainability during the crisis. The study bridges a literature gap by extending the Theory of Consumption Values and the Theory of Planned Behavior to SMEs that incorporate mobile-app-based business. Data was collected from 343 SMEs from three Industrial Development Corporations (IDCs) in India. Using the covariance-based structural equation modeling method, we investigated the efficiency of a conceptual model of mobile-app-based business for SMEs. The results revealed that consumer choice behavior, perceived behavior control, subjective behavior control and attitude towards the mobile app all influence SMEs' decision-making and business strategy. As such, SMEs need a powerful mobile-app-based business network to succeed in the entrepreneurial business process. Using instrumental variable analysis, we discovered that increased mobile app usage significantly improves SMEs' long-term efficiency. The analysis provides several theoretical and managerial ramifications.

Optimization of decoupling point position using metaheuristic evolutionary algorithms for smart mass customization manufacturing.

In this paper, we present two metaheuristic evolutionary algorithms-based approaches to position the customer order decoupling point (CODP) in smart mass customization (SMC). SMC tries to autonomously mass customize and produce products per customer needs in Industry 4.0. SMC shown here is from the perspective of arriving at a CODP during manufacturing process flow designs meant for fast moving and complex product variants. Learning generally needs several repetitive cycles to break the complexity barrier. We make use of fruit fly and particle swarm optimization (PSO) evolutionary algorithms with the help of MATLAB programming to constantly search better fitting consecutive process modules in manufacturing chain. CODP is optimized by increasing modularity and reducing complexity through evolutionary concept. Learning-based PSO iterations are performed. The methods shown here are recommended for process flow design in a learning-oriented supply chain organization which can involve in-house and outsourced manufacturing steps. Finally, a complexity reduction model is presented which can aid in deploying this concept in design of supply chain and manufacturing flows. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00521-020-05657-1.

Inkjet-printed co-continuous mesoporous oxides for high-current power transistors.

Limited printing resolution has always been a major hindrance for printed electronics; irrespective of the high mobility demonstrated by solution-processed semiconductors, long-channel printed field-effect transistors (FETs) have demonstrated low On-state conductance and switching speeds. Although various concepts have been proposed to obtain narrow-channel printed FETs, the actual demonstration of high On-currents/channel conductance has been rare. In this context, herein, we report a general recipe to print co-continuous mesoporous structures with high surface-to-volume ratios for the first time for a large range of metallic and semiconducting oxides, both n- and p-type; next, by exploiting an innovative transistor architecture by printing an additional silver layer on top of the printed porous channel, we reduced the necessary length of electronic transport through the semiconductor material to a short vertical distance of the order of a few tens of nanometres. Basically, when a composite solid polymer electrolyte was used as a gate insulator, we essentially obtained channel length-independent transport with the unprecedented On-current of 67 µA µm-1 and transconductance of 143 µS µm-1 at the supply voltage of only 0.5 V. Among others, one may foresee the usage of these devices in high power switches and for drawing power from batteries in all-printed electronic circuits.

Effect of semiconductor surface homogeneity and interface quality on electrical performance of inkjet-printed oxide field-effect transistors.

In semiconductor technology, the crystallite size of semiconductors is often directly correlated with their superior intrinsic and device mobility. However, when solution-processed, large crystals may bring in higher surface roughness and layer inhomogeneity, which can deteriorate the interface quality and device performance. Along this line, a thorough study on printed oxide field-effect transistors (FETs) has been performed, where the relative significance of crystallite size, surface roughness and spatial homogeneity are evaluated. The comprehensive investigations suggest the spatial homogeneity to be more important than crystallite size in solution processed/printed devices. It is demonstrated that the addition of a small amount of high boiling point polyol in the precursor ink can create large nucleation sites, resulting in reduced average crystallite size, superior inter-particle neck formation, and high spatial homogeneity. Interestingly, carefully estimated device mobility of these polyol-derived In2O3 FETs (∼50-55 cm2 V-1 s-1) is found to be larger than the FETs prepared without polyols, although the crystallite size of the former is an order of magnitude smaller. The high spatial homogeneity and the large mobility values of the polyol-derived In2O3 transistors, as compared to the amorphous oxide FETs, lowers the importance of the latter, at least within the solution-processed/printed electronics domain.

High-Performance All-Printed Amorphous Oxide FETs and Logics with Electronically Compatible Electrode/Channel Interface.

Oxide semiconductors typically show superior device performance compared to amorphous silicon or organic counterparts, especially when they are physical vapor deposited. However, it is not easy to reproduce identical device characteristics when the oxide field-effect transistors (FETs) are solution-processed/printed; the level of complexity further intensifies with the need to print the passive elements as well. Here, we developed a protocol for designing the most electronically compatible electrode/channel interface based on the judicious material selection. Exploiting this newly developed fabrication schemes, we are now able to demonstrate high-performance all-printed FETs and logic circuits using amorphous indium-gallium-zinc oxide (a-IGZO) semiconductor, indium tin oxide (ITO) as electrodes, and composite solid polymer electrolyte as the gate insulator. Interestingly, all-printed FETs demonstrate an optimal electrical performance in terms of threshold voltages and device mobility and may very well be compared with devices fabricated using sputtered ITO electrodes. This observation originates from the selection of electrode/channel materials from the same transparent semiconductor oxide family, resulting in the formation of In-Sn-Zn-O (ITZO)-based-diffused a-IGZO-ITO interface that controls doping density while ensuring high electrical performance. Compressive spectroscopic studies reveal that Sn doping-mediated excellent band alignment of IGZO with ITO electrodes is responsible for the excellent device performance observed. All-printed n-MOS-based logic circuits have also been demonstrated toward new-generation portable electronics.