Antonio Paone

Buildings consume a significant amount of energy, estimated at about one-third of total primary energy resources. Building energy efficiency has turned out to be a major issue in limiting the increasing energy demands of the sector. Literature shows that building user behavior can increase the efficiency of the energy used in the building and different strategies have been tested to address and support this issue. These strategies often combine the quantification of energy savings and qualitative interpretation of occupant behavior in order to foster energy efficiency. Strategies that influence building occupant behaviors include eco-feedback, social interaction, and gamification. This review paper presents a study conducted on the state of the art related to the impact of building user behavior on energy efficiency, in order to provide the research community with a better understanding and up-to-date knowledge of energy, comfort-related practices, and potential research opportunities. Achieving and maintaining energy-efficient behavior without decreasing the comfort of building occupants still represents a challenge, despite emerging technologies and strategies as well as general research progress made over the last decade. Conclusions highlight eco-feedback as an effective way to influence behavior, and gamification as a new opportunity to trigger behavioral change. The impact of user behavior is difficult to quantify for methodological reasons. Factors influencing human behavior are numerous and varied. Multi-disciplinary approaches are needed to provide new insights into the inner dynamic nature of occupant’s energy behavior.

We report a thorough investigation of the electrically-induced metal-insulator transition in vanadium dioxide (VO ₂ ) for abrupt switching in 2-terminal devices (0.24 mV/dec at 25 °C, 0.38 mV/dec at 50 °C). We exploit the electrothermal actuation model based on Joule heating to model and predict the low temperature dependence of the slope in VO ₂ switches.

This letter reports a detailed experimental investigation of the slope of the current switching between OFF and ON states exploiting the metal-insulator-transition (MIT) in vanadium dioxide devices. The reported devices are CMOS compatible two-terminal switches. We experimentally demonstrate for the first time the very little dependence on temperature of the steep slope of these switches, ranging from 0.24 mV/decade at room temperature, to 0.38 mV/decade at 50 °C. The fabricated devices show excellent ON-state conduction, with I _ON > 1.8 mA/μm or R _ON <; 3 mΩ/μm, for the whole range of investigated temperatures (from room temperature to the MIT transition temperature), which recommends them as future candidates for steep-slope, highly conductive, and temperature-stable switches.

We report the fabrication, modeling and characterization of novel microwave tunable capacitors based on the metal-insulator transition (MIT) of Vanadium Dioxide (VO ₂ ). We present the advantages of VO ₂ -based capacitors over alternative technologies for microwave reconfigurable electronics in terms of ease of integration, design and performance at high frequency. We show the potential of the proposed devices for RF reconfigurable electronics by fabricating a tunable bandstop filter (22.5-19.8 GHz) with insertion loss <; 2 dB up to 40 GHz.

We report an extensive experimental study of CMOS-compatible switches based on vanadium dioxide abrupt metal-insulator transition. We perform scaling studies to provide guidelines for optimization of the geometry of the VO ₂ device for integration on CMOS circuits, discussing the trade-off between the design parameters and the effect on performance for DC and RF applications. A VO ₂ thin film with resistivity varying from 5·10 ^-2 Ω·m in the insulating state to 1.5-10 ^-5 Ω·m in the conductive state allowed us to fabricate devices with actuation current ranging from 1.43 to 2.46 mA and resistance in the insulating state ranging from 5.8 kΩ to 35.9 kΩ. We identified a minimum actuation current of 5.75 μA for our technology, in a device miniaturized up to the limits of standard optical lithography. We show through RF measurements and simulations that the performance at high frequency of the switch can be improved using VO ₂ thin films with higher conductivity values, even if the contrast between the two states is lower.