Raman spectroscopy-based temperature sensing usually tracks the change of Raman wavenumber,linewidth and intensity,and has found very broad applications in characterizing the energy and charge transport in nanomateria...Raman spectroscopy-based temperature sensing usually tracks the change of Raman wavenumber,linewidth and intensity,and has found very broad applications in characterizing the energy and charge transport in nanomaterials over the last decade.The temperature coefficients of these Raman properties are highly material-dependent,and are subjected to local optical scattering influence.As a result,Raman-based temperature sensing usually suffers quite large uncertainties and has low sensitivity.Here,a novel method based on dual resonance Raman phenomenon is developed to precisely measure the absolute temperature rise of nanomaterial(nm WS_(2) film in this work)from 170 to 470 K.A 532 nm laser(2.33 eV photon energy)is used to conduct the Raman experiment.Its photon energy is very close to the excitonic transition energy of WS_(2) at temperatures close to room temperature.A parameter,termed resonance Raman ratio(R3)Ω=I_(A1g)/IE_(2g) is introduced to combine the temperature effects on resonance Raman scattering for the A_(1g) and E_(2g) modes.Ω has a change of more than two orders of magnitude from 177 to 477 K,and such change is independent of film thickness and local optical scattering.It is shown that when Ω is varied by 1%,the temperature probing sensitivity is 0.42 K and 1.16 K at low and high temperatures,respectively.Based on Ω,the in-plane thermal conductivity(k)of a∼25 nm-thick suspended WS_(2) film is measured using our energy transport state-resolved Raman(ET-Raman).k is found decreasing from 50.0 to 20.0 Wm^(−1) K^(−1) when temperature increases from 170 to 470 K.This agrees with previous experimental and theoretical results and the measurement data using our FET-Raman.The R3 technique provides a very robust and high-sensitivity method for temperature probing of nanomaterials and will have broad applications in nanoscale thermal transport characterization,non-destructive evaluation,and manufacturing monitoring.展开更多
Interfacial thermal resistance plays a crucial role in efficient heat dissipation in modern electronic devices.It is critical to understand the interfacial thermal transport from both experiments and underlying physic...Interfacial thermal resistance plays a crucial role in efficient heat dissipation in modern electronic devices.It is critical to understand the interfacial thermal transport from both experiments and underlying physics.This review is focused on the transient opto-thermal Raman-based techniques for measuring the interfacial thermal resistance between 2D materials and substrate.This transient idea eliminates the use of laser absorption and absolute temperature rise data,therefore provides some of the highest level measurement accuracy and physics understanding.Physical concepts and perspectives are given for the time-domain differential Raman(TD-Raman),frequency-resolved Raman(FRRaman),energy transport state-resolved Raman(ET-Raman),frequency domain ET-Raman(FET-Raman),as well as laser flash Raman and dual-wavelength laser flash Raman techniques.The thermal nonequilibrium between optical and acoustic phonons,as well as hot carrier diffusion must be considered for extremely small domain characterization of interfacial thermal resistance.To have a better understanding of phonon transport across material interfaces,we introduce a new concept termed effective interface energy transmission velocity.It is very striking that many reported interfaces have an almost constant energy transmission velocity over a wide temperature range.This physics consideration is inspired by the thermal reffusivity theory,which is effective for analyzing structure-phonon scattering.We expect the effective interface energy transmission velocity to give an intrinsic picture of the transmission of energy carriers,unaltered by the influence of their capacity to carry heat.展开更多
基金Support of this work by National Science Foundation(CBET1930866 and CMMI2032464 for X W)National Natural Science Foundation of China(No.52106220 for S X and No.51906161 for Y X)。
文摘Raman spectroscopy-based temperature sensing usually tracks the change of Raman wavenumber,linewidth and intensity,and has found very broad applications in characterizing the energy and charge transport in nanomaterials over the last decade.The temperature coefficients of these Raman properties are highly material-dependent,and are subjected to local optical scattering influence.As a result,Raman-based temperature sensing usually suffers quite large uncertainties and has low sensitivity.Here,a novel method based on dual resonance Raman phenomenon is developed to precisely measure the absolute temperature rise of nanomaterial(nm WS_(2) film in this work)from 170 to 470 K.A 532 nm laser(2.33 eV photon energy)is used to conduct the Raman experiment.Its photon energy is very close to the excitonic transition energy of WS_(2) at temperatures close to room temperature.A parameter,termed resonance Raman ratio(R3)Ω=I_(A1g)/IE_(2g) is introduced to combine the temperature effects on resonance Raman scattering for the A_(1g) and E_(2g) modes.Ω has a change of more than two orders of magnitude from 177 to 477 K,and such change is independent of film thickness and local optical scattering.It is shown that when Ω is varied by 1%,the temperature probing sensitivity is 0.42 K and 1.16 K at low and high temperatures,respectively.Based on Ω,the in-plane thermal conductivity(k)of a∼25 nm-thick suspended WS_(2) film is measured using our energy transport state-resolved Raman(ET-Raman).k is found decreasing from 50.0 to 20.0 Wm^(−1) K^(−1) when temperature increases from 170 to 470 K.This agrees with previous experimental and theoretical results and the measurement data using our FET-Raman.The R3 technique provides a very robust and high-sensitivity method for temperature probing of nanomaterials and will have broad applications in nanoscale thermal transport characterization,non-destructive evaluation,and manufacturing monitoring.
基金supported by the National Natural Science Foundation of China(No.12204320 for J.L.and 52276080 for Y.X.)US National Science Foundation(CBET1930866 and CMMI2032464 for X.W)J.L.is grateful for the support from Shenzhen Science and Technology Program(JCYJ20220530153401003).
文摘Interfacial thermal resistance plays a crucial role in efficient heat dissipation in modern electronic devices.It is critical to understand the interfacial thermal transport from both experiments and underlying physics.This review is focused on the transient opto-thermal Raman-based techniques for measuring the interfacial thermal resistance between 2D materials and substrate.This transient idea eliminates the use of laser absorption and absolute temperature rise data,therefore provides some of the highest level measurement accuracy and physics understanding.Physical concepts and perspectives are given for the time-domain differential Raman(TD-Raman),frequency-resolved Raman(FRRaman),energy transport state-resolved Raman(ET-Raman),frequency domain ET-Raman(FET-Raman),as well as laser flash Raman and dual-wavelength laser flash Raman techniques.The thermal nonequilibrium between optical and acoustic phonons,as well as hot carrier diffusion must be considered for extremely small domain characterization of interfacial thermal resistance.To have a better understanding of phonon transport across material interfaces,we introduce a new concept termed effective interface energy transmission velocity.It is very striking that many reported interfaces have an almost constant energy transmission velocity over a wide temperature range.This physics consideration is inspired by the thermal reffusivity theory,which is effective for analyzing structure-phonon scattering.We expect the effective interface energy transmission velocity to give an intrinsic picture of the transmission of energy carriers,unaltered by the influence of their capacity to carry heat.
