Limits...
Electrical Switching in Semiconductor-Metal Self-Assembled VO 2 Disordered Metamaterial Coatings

View Article: PubMed Central - PubMed

ABSTRACT

As a strongly correlated metal oxide, VO2 inspires several highly technological applications. The challenging reliable wafer-scale synthesis of high quality polycrystalline VO2 coatings is demonstrated on 4” Si taking advantage of the oxidative sintering of chemically vapor deposited VO2 films. This approach results in films with a semiconductor-metal transition (SMT) quality approaching that of the epitaxial counterpart. SMT occurs with an abrupt electrical resistivity change exceeding three orders of magnitude with a narrow hysteresis width. Spatially resolved infrared and Raman analyses evidence the self-assembly of VO2 disordered metamaterial, compresing monoclinic (M1 and M2) and rutile (R) domains, at the transition temperature region. The M2 mediation of the M1-R transition is spatially confined and related to the localized strain-stabilization of the M2 phase. The presence of the M2 phase is supposed to play a role as a minor semiconducting phase far above the SMT temperature. In terms of application, we show that the VO2 disordered self-assembly of M and R phases is highly stable and can be thermally triggered with high precision using short heating or cooling pulses with adjusted strengths. Such a control enables an accurate and tunable thermal control of the electrical switching.

No MeSH data available.


Schematic representation of the thermal switching process based on the hysteresis curve.The impact of adopting two different amplitudes of the thermal activation is illustrated in (i) and (ii). c → a → b: cooling pulse; b → d → c: heating pulse.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5121613&req=5

f10: Schematic representation of the thermal switching process based on the hysteresis curve.The impact of adopting two different amplitudes of the thermal activation is illustrated in (i) and (ii). c → a → b: cooling pulse; b → d → c: heating pulse.

Mentions: Experimental thermal switching behavior of VO2 is displayed in Fig. 9. At the background temperature 67 °C the VO2 films feature the disordered metamaterial structure. This temperature is applied using a heating stage while monitoring the electrical resistance. The highly resistive semiconducting state is considered as an “off” state. A 3 seconds heating pulse ΔT drives the coalescence of the metallic rutile domains in the metamaterial, a state that is retained after the back stabilization of the temperature at 67 °C. This behavior originates from the difference between the forward and backward transition temperatures due to hysteresis width as illustrated schematically in Fig. 10. In order to switch the metamaterial back to the “off” state, a cooling pulse for a short duration induces the shrinkage and confinement of the metallic domains. Consequently, the metamaterial features a resistive semiconducting behavior even when it stabilized back at 67 °C. Hence, short thermal activation pulses are reliably implemented for abrupt manipulation of the electrical properties of VO2 in the metamaterial state. The amplitude of the thermal pulse activation has a direct impact on the response of VO2 metamaterial as shown in Figs 9 and 10.


Electrical Switching in Semiconductor-Metal Self-Assembled VO 2 Disordered Metamaterial Coatings
Schematic representation of the thermal switching process based on the hysteresis curve.The impact of adopting two different amplitudes of the thermal activation is illustrated in (i) and (ii). c → a → b: cooling pulse; b → d → c: heating pulse.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121613&req=5

f10: Schematic representation of the thermal switching process based on the hysteresis curve.The impact of adopting two different amplitudes of the thermal activation is illustrated in (i) and (ii). c → a → b: cooling pulse; b → d → c: heating pulse.
Mentions: Experimental thermal switching behavior of VO2 is displayed in Fig. 9. At the background temperature 67 °C the VO2 films feature the disordered metamaterial structure. This temperature is applied using a heating stage while monitoring the electrical resistance. The highly resistive semiconducting state is considered as an “off” state. A 3 seconds heating pulse ΔT drives the coalescence of the metallic rutile domains in the metamaterial, a state that is retained after the back stabilization of the temperature at 67 °C. This behavior originates from the difference between the forward and backward transition temperatures due to hysteresis width as illustrated schematically in Fig. 10. In order to switch the metamaterial back to the “off” state, a cooling pulse for a short duration induces the shrinkage and confinement of the metallic domains. Consequently, the metamaterial features a resistive semiconducting behavior even when it stabilized back at 67 °C. Hence, short thermal activation pulses are reliably implemented for abrupt manipulation of the electrical properties of VO2 in the metamaterial state. The amplitude of the thermal pulse activation has a direct impact on the response of VO2 metamaterial as shown in Figs 9 and 10.

View Article: PubMed Central - PubMed

ABSTRACT

As a strongly correlated metal oxide, VO2 inspires several highly technological applications. The challenging reliable wafer-scale synthesis of high quality polycrystalline VO2 coatings is demonstrated on 4” Si taking advantage of the oxidative sintering of chemically vapor deposited VO2 films. This approach results in films with a semiconductor-metal transition (SMT) quality approaching that of the epitaxial counterpart. SMT occurs with an abrupt electrical resistivity change exceeding three orders of magnitude with a narrow hysteresis width. Spatially resolved infrared and Raman analyses evidence the self-assembly of VO2 disordered metamaterial, compresing monoclinic (M1 and M2) and rutile (R) domains, at the transition temperature region. The M2 mediation of the M1-R transition is spatially confined and related to the localized strain-stabilization of the M2 phase. The presence of the M2 phase is supposed to play a role as a minor semiconducting phase far above the SMT temperature. In terms of application, we show that the VO2 disordered self-assembly of M and R phases is highly stable and can be thermally triggered with high precision using short heating or cooling pulses with adjusted strengths. Such a control enables an accurate and tunable thermal control of the electrical switching.

No MeSH data available.