HfO2-based nanostructured thin-films (i.e., low-e coatings) with robust optical performance and energy efficiency

This study investigates the electronic, optical, and thermo electronic properties executed by First Principles and experimental examination on undoped HfO2 and Copper (Cu) based transition metal oxides (HfO2) nanostructured thin films. Thermoelectric properties of undoped HfO2 by semi-classical Boltzmann transport theory were carried out using the BotlzTraP code. Copper (Cu) based transition metal oxides (HfO2) nanostructured thin films have been designed on properly cleaned micro slides of CORNING glass substrate with dimensions of 70 x 50 mm and thickness 0.96-1.06 mm using electron beam evaporation. During deposition, the substrate temperature has been varied from 30 to 150 degrees C maintaining the overall thickness at similar to 25 nm through crystal quartz monitor. Surface morphology, optical properties, including optical parameters, have been measured precisely with high resolution. Atomic Force Microscopy (AFM) has been employed for films morphology, grain sizes, and roughness. Using Gwyddion software, for all the samples at 30 degrees C (namely AZ-I), 100 degrees C (AZ-II), and 150 degrees C (AZ-III) substrate temperature, the root mean square (RMS) roughness calculated as 2.56 nm, 5.04 nm, and 4.32 nm, respectively. Whereas, the grain size was verified as 17.42 nm, 21.49 nm, and 24.87 nm respectively along with other surface parameters proved that the film's surface density and crystallinity were improved by increasing substrate temperature. Optical properties transmittance and reflectance were measured Dual beam Perkin-Elmer spectrophotometer-950 ranging from 250 to 2500 nm (UV-VIS-NIR). The overall changes in transmittance showed the maximum value (above 70%) in the visible region whereas minimum (below 10%) for NIR and IR regions of the light spectrum for all the samples AZ-I, AZ-II, and AZ-III. Other concerned optical constants like refractive indices, molar reflectivity, and extinction coefficients were also calculated. Their variations and performances have been proved that the deposited D/M/D nanostructured films were favorable as optically active films and energy efficient windows. The simulations and experimental results show association in electronic and optical parameters. [GRAPHICS] .

Automated summary

This study investigated the electronic, optical, and thermo electronic properties of undoped HfO2 and copper-based transition metal oxides nanostructured thin films through First Principles and experimental examination. The results showed that increasing substrate temperature improved the surface density and crystallinity of the films, leading to enhanced optical activity.