Multivalued logic (MVL) computing could provide bit density beyond that of Boolean logic. Unlike conventional transistors, heterojunction transistors (H‐TRs) exhibit negative transconductance (NTC) regions. Using the NTC characteristics of H‐TRs, ternary inverters have recently been demonstrated. However, they have shown incomplete inverter characteristics; the output voltage (VOUT) does not fully swing from VDD to GND. A new H‐TR device structure that consists of a dinaphtho[2,3‐b:2′,3′‐f]thieno[3,2‐b]thiophene (DNTT) layer stacked on a PTCDI‐C13 layer is presented. Due to the continuous DNTT layer from source to drain, the proposed device exhibits novel switching behavior: p‐type off/p‐type subthreshold region /NTC/ p‐type on. As a result, it has a very high on/off current ratio (≈105) and exhibits NTC behavior. It is also demonstrated that an array of 36 of these H‐TRs have 100% yield, a uniform on/off current ratio, and uniform NTC characteristics. Furthermore, the proposed ternary inverter exhibits full VDD‐to‐GND swing of VOUT with three distinct logic states. The proposed transistors and inverters exhibit hysteresis‐free operation due to the use of a hydrophobic gate dielectric and encapsulating layers. Based on this, the transient operation of a ternary inverter circuit is demonstrated for the first time.

Multilayer MoS has been gaining interest as a new semiconducting material for flexible displays, memory devices, chemical/biosensors, and photodetectors. However, conventional multilayer MoS devices have exhibited limited performances due to the Schottky barrier and defects. Here, we demonstrate poly(diketopyrrolopyrrole-terthiophene) (PDPP3T) doping effects in multilayer MoS, which results in improved electrical characteristics (∼4.6× higher on-current compared to the baseline and a high current on/off ratio of 10). Synchrotron-based study using X-ray photoelectron spectroscopy and grazing incidence wide-angle X-ray diffraction provides mechanisms that align the edge-on crystallites (97.5%) of the PDPP3T as well as a larger interaction with MoS that leads to dipole and charge transfer effects (at annealing temperature of 300 °C), which support the observed enhancement of the electrical characteristics. Furthermore, we demonstrate a complementary metal-oxide-semiconductor inverter that uses a p-type MoSe and a PDPP3T-doped MoS as charging and discharging channels, respectively.

Metal oxide semiconductors are of great interest for enabling advanced photodetectors. However, operational instability and the absence of an appropriate doping technique hinder practical development and commercialization. Here, a strategy is proposed to dramatically increase the conventional photodetection performance, having superior stability in operational and environmental atmospheres. By performing energy‐band engineering through an octadecylphosphonic acid (ODPA) self‐assembled‐monolayer‐based doping treatment, the proposed indium–gallium–zinc oxide (IGZO)/p‐Si heterointerface devices exhibit greatly enhance the photoresponsive characteristics, including a photoswitching current ratio with a 100‐fold increase, and photoresponsivity and detectivity with a 15‐fold increase each. The observed ODPA doping effects are investigated through comprehensive analysis with X‐ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and Kelvin probe force microscopy (KPFM). Furthermore, the proposed photodetectors, fabricated at a 4 in. wafer scale, demonstrate its excellent operation robustness with consistent performance over 237 days and 20 000 testing cycles.

Multilayer transition metal dichalcogenides (TMDs) potentially provide opportunities for large‐area electronics, including flexible displays and wearable sensors. However, most TMDs suffer from a Schottky barrier (SB) and nonuniform defects, which severely limit their electrical performances. Here, a novel chemical doping scheme is presented using poly‐(diketopyrrolopyrrole‐terthiophene) (PDPP3T) to compensate the defects and SB of multilayer molybdenum diselenide (MoSe2), exhibiting greatly enhanced electrical characteristics, including on‐current (≈2000‐fold higher) and photoresponsivity (≈10‐fold larger) over the baseline MoSe2 device. Based on comprehensive analysis using X‐ray photoelectron spectroscopy, grazing incidence wide‐angle X‐ray diffraction, atomic force microscopy, and near‐edge X‐ray absorption of fine structure, it is shown that two mechanisms (dipole‐induced and charge‐transfer doping effects) account for such enhancements in the multilayer MoSe2 device. The methodical generality of the strong n‐doping behavior of multilayer MoSe2 is further demonstrated by applying thiophene instead of PDPP3T.

Multilevel metal interconnects are crucial for the development of large-scale organic integrated circuits. In particular, three-dimensional integrated circuits require a large number of vertical interconnects between layers. Here, we present a novel multilevel metal interconnect scheme that involves solvent-free patterning of insulator layers to form an interconnecting area that ensures a reliable electrical connection between two metals in different layers. Using a highly reliable interconnect method, the highest stacked organic transistors to date, a three-dimensional organic integrated circuits consisting of 5 transistors and 20 metal layers, is successfully fabricated in a solvent-free manner. All transistors exhibit outstanding device characteristics, including a high on/off current ratio of ~10 7 , no hysteresis behavior, and excellent device-to-device uniformity. We also demonstrate two vertically-stacked complementary inverter circuits that use transistors on 4 different floors. All circuits show superb inverter characteristics with a 100% output voltage swing and gain up to 35 V per V.