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The SrTiO3/Si system was initially studied to develop a basic understanding of the integration of perovskite oxides with semiconductors, and successful integration with abrupt interfaces was demonstrated. Defect analysis showed no misfit dislocations but only anti-phase boundaries (APBs) in the SrTiO3 (STO) films. Similar defects were later observed in other perovskite oxide heterostructures.
Ferroelectric BaTiO3 (BTO) thin films deposited directly onto STO substrates, or STO buffer layers with Ge substrates, were grown by molecular beam epitaxy (MBE) in order to control the polarization orientation for field-effect transistors (FETs). STEM imaging and elemental mapping by electron energy-loss spectroscopy (EELS) showed structurally and chemically abrupt interfaces, and the BTO films retained the c-axis-oriented tetragonal structure for both BTO/STO and BTO/STO/Ge heterostructures. The polarization displacement in the BTO films of TiN/BTO/STO heterostructures was investigated. The Ti4+ atomic column displacements and lattice parameters were measured directly using HAADF images. A polarization gradient, which switched from upwards to downwards, was observed in the BTO thin film, and evidence was found for positively-charged oxygen vacancies.
Heterostructures grown on Ge substrates by atomic layer deposition (ALD) were characterized and compared with MBE-grown samples. A two-step process was needed to overcome interlayer reaction at the beginning of ALD growth. A-site-rich oxide films with thicknesses of at least 2-nm had to be deposited and then crystallized before initiating deposition of the following perovskite oxide layer in order to suppress the formation of amorphous oxide layers on the Ge surface. BTO/STO/Ge, BTO/Ge, SrHfTiO3/Ge and SrZrO3/Ge thin films with excellent crystallinity were grown using this process.
Metal-insulator-metal (MIM) heterostructures were fabricated as ferroelectric capacitors and then electrically stressed to the point of breakdown to correlate structural changes with electrical and physical properties. BaTiO3 on Nb:STO was patterned with different top metal electrodes by focused-ion-beam milling, Au/Ni liftoff, and an isolation-defined approach.
Careful considerations in designing and organizing information for restaurant point-of-sale (POS) systems can affect user experience. Unfortunately, usability guidelines are sparse for these systems. Applications from other studies, such as categorical organization and F-shape, are implemented in an experimental interface as a starting point of discussion. A control interface was designed after the default version of NCR Aloha’s POS program: Aloha Table Service. Novice and expert order taking strategies were also observed to compare input differences. This study examined selection time, total time, and selection accuracy across both order and interface types. The results show that time and number of key presses are significantly reduced under the treatment interface, and that teaching expert order taking strategies to novice users may help reduce cognitive load.
The habit loop underlies this whole process. First, someone has a craving--food, happiness, stress relief, anything. Next, they experience a cue in the environment--a sight, sound, smell, or piece of information that prompts them to act. Then they perform the routine, which is the most visible part of a habit. Finally, they are rewarded, whether the reward is good for them in the long run or not. We perform habits all the time without realizing it, so having even slightly more awareness and control of our habits can have a disproportionate benefit for our personal improvement.
In its earliest iterations, “habit trackers” were paper tools for measuring and motivating daily progress. Many competitors are still paper, like journals and calendars. Others are apps with the same functionality. In my competitive analysis, I chose to focus on competitors that included a behavioral change component along with habit tracking.