heat-dissipation structures, such as fins and micro/nanochannels, have been designed to efficiently dissipate heat from heat sources. [4][5][6] However, the inevitable gap between the heat source and heat exchanger results in thermal contact resistance (R c ), deteriorating heat dissipation performance. [7,8] The R c can be decreased by filling the gap with a thermal interface material (TIM). [1,7] A variety of different TIMs are available including thermal greases, adhesives, solders, and pads. [9] The pad-type TIM is a pre-formed thermally conductive film which can be compressed between the heat source and heat sink. This is removable which is advantageous for future disassembly and reassembly of the heat sink.The TIM can be classified based on directionality. [10] An anisotropic TIM, such as a graphite sheet, provides a high thermal conductivity (κ) in the aligned direction (≈1500 W m −1 K −1 ), but the κ in the perpendicular direction is significantly lower (≈5 W m −1 K −1 ). [11] Directional heat manipulation has been actively investigated using aligned hexagonal boron nitride platelets, [12] thermal metamaterials, [13,14] and aperiodic superlattice structures. [15,16] These technologies have potential applications in anisotropic TIMs. An isotropic TIM provides a uniform κ in all directions and can be synthesized by dispersing randomly-oriented thermally conductive fillers in a polymer matrix. [10,17,18] The κ of commercial isotropic TIMs is typically small (≈10 W m −1 K −1 ). Various types of fillers, such as carbon nanotubes, graphene, boron nitrides, metal nanoparticles (NPs), and ceramic particles, have been actively investigated to enhance κ. [10,17,[19][20][21][22] Polyurethane, epoxy (EP), and silicone rubber have been employed as a matrix to achieve high compressibility and conformability. [10,17,19,23] In this study, pad-type isotropic polymeric TIMs are primarily analyzed.Another important parameter of TIMs, in addition to κ, is thermal resistance. [24] The total thermal resistance (R t ) is composed of the specimen thermal resistance (R s = l/κ, l = specimen thickness) and R c . In order to decrease R s , the κ of TIMs can be increased by increasing filler concentration. However, the high filler concentration also increases elastic modulus (E), or decreases softness, making the conformal contact with a matingThe ORCID identification number(s) for the author(s) of this article can be found under

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.

No abstract

No abstract

Earth-abundant and inexpensive transition metal dichalcogenides (TMDCs) with existing polymorphisms (metallic 1T phase and semiconducting 2H phase) have been proposed as alternatives to noble metals (e.g., Pt, Ir, and Ru) to achieve an efficient hydrogen evolution reaction (HER). Although the 1T phase of TMDCs (1T-TMDCs) is essential as an HER catalyst, practical application in the HER has not been realized owing to the lack of any large-scale production of the 1T-TMDC and 1T/1T-TMDC heterostructure fabrication method. Here, polymorphic TMDC–TMDC heterostructures at a 4 in. wafer scale is reported for 1T-MoS2/1T-WS2 vertical heterostructures (1T/1T-MWH) or 2H-MoS2/2H-WS2 vertical heterostructures (2H/2H-MWH) under cold plasma conditions and process temperature. Simultaneous ion-bombardment onto substrates induces a few nanosized grain boundaries with discontinuous films, resulting in exposed edges that act as catalytically active sites. The electrocatalytic performances of the prepared polymorph (1T or 2H phases of MoS2 and WS2) and polymorphic heterostructures of 1T/1T-MWH and 2H/2H-MWH are compared. 1T/1T-MWH shows the highest electrocatalytic performance owing to its metallic 1T phase and heterostructures containing alloy structures at the heterointerface. Moreover, the nanosized grains of 1T/1T-MWH preserve their original phase after 1000 HER cycles, proving their robustness and durability.