Structural colors are fascinating due to their stability in comparison with dyes and pigments; nevertheless, environmental pollutants contaminate surfaces and redefine structural colors. To overcome this problem, cleaning of the surface is necessary at regular intervals, which is cumbersome and costly. We have circumvented this issue in this article and fabricated scalable self-cleaning structural colors. The structural colors are generated by TiO 2 nanorods and thin films on Ti sputtered glass and flexible polyethylene terephthalate substrates employing a glancing angle deposition (GLAD) technique. Theoretical calculations based on thin film interference validate the experimental results and suggest Al, Ni, Co, and Cu as an alternative of Ti for generating structural colors. Structural colors are transformed to a superhydrophilic state, i.e., a self-cleaning state, via UV exposure and annealing at elevated temperatures. In addition to a self-cleaning state, annealing could control the opaqueness and color tunability of the structural colors. A permanent wettability state in between the superhydrophobic and superhydrophilic states of the structural colors is controlled by the GLAD technique. Moreover, the structural colors are demonstrated for information encryption and optical ethanol sensing applications.

Vertical organic field effect transistors (VOFETs) are of paramount importance due to their fast switching speed, low power consumption, and higher density on a chip compared to lateral OFETs. The low charge carrier mobility in organic semiconductors and longer channel lengths in lateral OFETs lead to higher operating voltages. The channel length in VOFETs can be less than 100 nm which reduces the size of the channel and hence the operating voltages. Another important factor in the operation of VOFETs is the thickness and width of the source electrode. The channel length, source electrode thickness and width sets the miniaturization limit of the VOFETs. The graphene monolayer can be exploited as a source electrode due to its thinness, high carrier mobility, and metallic behaviors. However, for better gate modulation, perforations in the source material are desired. Here, we simulate the VOFET having perforated graphene monolayer as a source electrode and n-type organic semiconductor N, N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8) as an active channel material, while aluminum as a drain electrode to predict the best-miniaturized device. The miniaturization limit of such a VOFET has a limit to the gate opening/perforation in which the minimum source width is 10 nm, as in the sub 10 nm range graphene starts behaving like a semiconductor. The subthreshold swing, deduced from the drain current (J _D) versus gate voltage (V _G) graph, advocates the limit of the organic semiconductor height/channel length to 50 nm, while 50 nm for the gate.

Indium Arsenide is a III–V semiconductor with low electron effective mass, a small band gap, strong spin–orbit coupling, and a large g-factor. These properties and its surface Fermi level pinned in the conduction band make InAs a good candidate for developing superconducting solid-state quantum devices. Here, we report the epitaxial growth of very thin InAs layers with thicknesses ranging from 12.5 nm to 500 nm grown by Molecular Beam Epitaxy on In_xAl_1−xAs metamorphic buffers. Differently than InAs substrates, these buffers have the advantage of being insulating at cryogenic temperatures, which allows for multiple device operations on the same wafer and thus making the approach scalable. The structural properties of the InAs layers were investigated by high-resolution X-ray diffraction, demonstrating the high crystal quality of the InAs layers. Furthermore, their transport properties, such as total and sheet carrier concentration, sheet resistance, and carrier mobility, were measured in the van der Pauw configuration at room temperature. A simple conduction model was employed to quantify the surface, bulk, and interface contributions to the overall carrier concentration and mobility.