Smooth mesoporous silica films (see Figure) can now be obtained with very low dielectric constants by spin coating, whereby the thickness and hydrophobicity of the films can also be controlled. This is thanks to a functionalized precursor as is unveiled in this communication. These films are sure to be on the wanted list for semiconductor applications as they combine dielectric stability with a low processing temperature, an excellent thermal stability, and reliable mechanical properties.

Oxygen plasma has been successfully utilized to remove the organic template in molecularly templated nanoporous silica films. The resulting nanoporous silica film has a high porosity and a surface roughness of less than 10 Å. The hydrophilic film can be modified to be hydrophobic by reacting with hexamethyldisilazane ͑HMDS͒. Reductive plasmas, such as hydrogen and ammonia plasmas, have been applied to reduce the leakage current of the nanoporous silica film without deteriorating the dielectric properties. The dielectric constant of the silica film can be reduced to 1.7 after an HMDS/H 2 plasma/HMDS treatment. The leakage current of the plasma-treated silica film can reach below 1 ϫ 10 Ϫ7 A/cm 2 at an electric field of 2 MV/cm. This report shows the feasibility of integration of plasma processes into preparation of molecularly templated nanoporous silica films for ULSI applications.

Developing a methodology to enhance long-term stability is one of the most important issues in MXene research, since they are prone to oxidation in the ambient environment. Although various approaches have been suggested to improve the stability of MXene, they have suffered from complicated processes and limited applicability to various types of MXene nanostructures. Herein, we report a simple and versatile technique to enhance the environmental stability of MXenes. Ti3C2T x MXene films were decorated with a highly hydrophobic polymer, 1H,1H,2H,2H-perfluorodecyl methacrylate (PFDMA), using initiated chemical vapor deposition (iCVD) where iCVD allows the facile postdeposition of polymer films of desired thickness on MXene films. The oxidation resistance was evaluated by fabricating MXene gas sensors and measuring the change in signal-to-noise ratio (SNR) of volatile organic compound (VOC) gases under harsh conditions (RH 100% at 50 °C) for several weeks where the performance in the absence and presence of PFDMA was compared. The results show that while the SNR of PFDMA-Ti3C2T x sensors was retained, a dramatic increase of the noise level and a decrease in the SNR were observed in pristine Ti3C2T x . We believe that this simple and nondestructive method will offer great potential to enhance the stability of a wide range of MXenes.