Motivation: Thermal management is one of the main challenges for modern electronics, especially for high-power and high-frequency applications such as radar systems, satellite communications, automative cars, 5G, and internet of things. Localized self-heating in these devices degrades device performance and reliability, shortens device lifetime, and causes safety issues. Understanding fundamental transport mechanisms and developing proper thermal engineering techniques facilitate solving the thermal problems.
Summary: My postdoc work focuses on thermal science and engineering in Li-ion battery (US Army CERL battery project). For my PhD study, I worked on one DARPA Round Robin diamond project (2015-2017), one AFOSR memristor MURI (2017-2018), one ONR thermal interface MURI (2018-) and one AFOSR Ga2O3 MURI (2018-). The details of my work on each project are shown below.
Summary: My postdoc work focuses on thermal science and engineering in Li-ion battery (US Army CERL battery project). For my PhD study, I worked on one DARPA Round Robin diamond project (2015-2017), one AFOSR memristor MURI (2017-2018), one ONR thermal interface MURI (2018-) and one AFOSR Ga2O3 MURI (2018-). The details of my work on each project are shown below.
|
|
|
|
UIUC: US Amy Construction Engineering Research Lab (CERL) battery project (2020-)
1. The goals of High Energy Density Anode Technologies (HEDAT) are to discover, understand, and engineer new materials for anodes, cathodes, and solid electrolytes that take advantage of anodes with higher energy density than carbon.
Selected Publications:
1. Cheng, Zhe, et al. "Good Solid-State Electrolytes Have Low, Glass-like Thermal Conductivity", Small, 2021
2. Cheng, Zhe, et al. "Direct Observation of Reversible Heat Absorption in Li-ion Battery Enabled by Ultra-sensitive Thermometry", Journal of Power Source (Under review), arXiv: 2107.00625, 2021
3. Ji, Xiaoyang, Cheng, Zhe, Ella, Pek, Cahill, David. "Thermal Conductivity Mapping of Oxidized SiC-SiC Composites by Time Domain Thermoreflectance with Heterodyne Dection", Journal of American Ceramic Society, 2021
4. Cheng, Zhe, et al. "Li-ion Battery with zero net heat generation during charging", (in preparation), 2021.
1. The goals of High Energy Density Anode Technologies (HEDAT) are to discover, understand, and engineer new materials for anodes, cathodes, and solid electrolytes that take advantage of anodes with higher energy density than carbon.
Selected Publications:
1. Cheng, Zhe, et al. "Good Solid-State Electrolytes Have Low, Glass-like Thermal Conductivity", Small, 2021
2. Cheng, Zhe, et al. "Direct Observation of Reversible Heat Absorption in Li-ion Battery Enabled by Ultra-sensitive Thermometry", Journal of Power Source (Under review), arXiv: 2107.00625, 2021
3. Ji, Xiaoyang, Cheng, Zhe, Ella, Pek, Cahill, David. "Thermal Conductivity Mapping of Oxidized SiC-SiC Composites by Time Domain Thermoreflectance with Heterodyne Dection", Journal of American Ceramic Society, 2021
4. Cheng, Zhe, et al. "Li-ion Battery with zero net heat generation during charging", (in preparation), 2021.
Georgia Tech: DOD Office of Naval Research (ONR) thermal interface MURI (2018-)
1. Interfacial thermal transport across harmonic interfaces to study elastic/inelastic process of phonon scatterings
2. Experimental observation of intrinsic thermal conductivity of AlN
3. Thermal transport across heterogeneously integrated interfaces by room-temperature surface-activated bonding for GaN-on-SiC and GaN-on-diamond applications.
Selected Publications:
1. Cheng, Zhe, et al. "Experimental Observation of Localized Interfacial Phonon Modes", Nature Communications, (accepted), 2021.
2. Cheng, Zhe, et al. "Thermal Visualization of Buried Interfaces Enabled by Ratio Signal and Steady-state Heating of Time-Domain Thermoreflectance", ACS Applied Materials&Interfaces, 13(27), 31843-31851.
3. Cheng, Zhe, et al. "Interfacial Thermal Conductance across Room-Temperature-Bonded GaN/Diamond Interfaces for GaN-on-Diamond Devices." ACS Applied Materials & Interfaces 12.7 (2020): 8376-8384.
4. Cheng, Zhe, et al. "Thermal Conductance across Harmonic-Matched Epitaxial Al-Sapphire Heterointerfaces." Nature Communication Physics, 3, 115 (2020).
5. Cheng, Zhe, et al. "Experimental Observation of High Intrinsic Thermal Conductivity of AlN."Physical Review Materials, 4(4), 044602, (2020).
6. Mu, Fengwen*, Cheng Zhe*, et al. "High Thermal Boundary Conductance across Bonded Heterogeneous GaN–SiC Interfaces." ACS applied materials & interfaces 11.36 (2019): 33428-33434.
7. Cheng, Zhe, et al. "Tunable Thermal Energy Transport across Diamond Membranes and Diamond–Si Interfaces by Nanoscale Graphoepitaxy." ACS applied materials & interfaces 11.20 (2019): 18517-18527.
8. Gaskins, John T., et al. "Thermal boundary conductance across heteroepitaxial ZnO/GaN interfaces: Assessment of the phonon gas model." Nano letters 18.12 (2018): 7469-7477.
9. Cheng, Zhe, et al. "Quasi-Ballistic Thermal Conduction in 6H-SiC", Materials Today Physics, 20, 100462, 2021.
1. Interfacial thermal transport across harmonic interfaces to study elastic/inelastic process of phonon scatterings
2. Experimental observation of intrinsic thermal conductivity of AlN
3. Thermal transport across heterogeneously integrated interfaces by room-temperature surface-activated bonding for GaN-on-SiC and GaN-on-diamond applications.
Selected Publications:
1. Cheng, Zhe, et al. "Experimental Observation of Localized Interfacial Phonon Modes", Nature Communications, (accepted), 2021.
2. Cheng, Zhe, et al. "Thermal Visualization of Buried Interfaces Enabled by Ratio Signal and Steady-state Heating of Time-Domain Thermoreflectance", ACS Applied Materials&Interfaces, 13(27), 31843-31851.
3. Cheng, Zhe, et al. "Interfacial Thermal Conductance across Room-Temperature-Bonded GaN/Diamond Interfaces for GaN-on-Diamond Devices." ACS Applied Materials & Interfaces 12.7 (2020): 8376-8384.
4. Cheng, Zhe, et al. "Thermal Conductance across Harmonic-Matched Epitaxial Al-Sapphire Heterointerfaces." Nature Communication Physics, 3, 115 (2020).
5. Cheng, Zhe, et al. "Experimental Observation of High Intrinsic Thermal Conductivity of AlN."Physical Review Materials, 4(4), 044602, (2020).
6. Mu, Fengwen*, Cheng Zhe*, et al. "High Thermal Boundary Conductance across Bonded Heterogeneous GaN–SiC Interfaces." ACS applied materials & interfaces 11.36 (2019): 33428-33434.
7. Cheng, Zhe, et al. "Tunable Thermal Energy Transport across Diamond Membranes and Diamond–Si Interfaces by Nanoscale Graphoepitaxy." ACS applied materials & interfaces 11.20 (2019): 18517-18527.
8. Gaskins, John T., et al. "Thermal boundary conductance across heteroepitaxial ZnO/GaN interfaces: Assessment of the phonon gas model." Nano letters 18.12 (2018): 7469-7477.
9. Cheng, Zhe, et al. "Quasi-Ballistic Thermal Conduction in 6H-SiC", Materials Today Physics, 20, 100462, 2021.
Georgia Tech: DOD Air Force Office of Scientific Research (AFOSR) Ga2O3 GAME MURI (2018-2019)
1. Integration of high thermal conductivity substrates with Ga2O3 for thermal management
2. Thermal conduction in Ga2O3 nanostructures.
Selected Publications:
1. Cheng, Zhe, et al. "Thermal conductance across β-Ga2O3-diamond van der Waals heterogeneous interfaces." APL Materials 7.3 (2019): 031118.
2. Cheng, Zhe, et al. "Integration of polycrystalline Ga2O3 on diamond for thermal management." Applied Physics Letters116.6 (2020): 062105.
3. Cheng, Zhe, et al. "Significantly reduced thermal conductivity in β-(Al0. 1Ga0. 9) 2O3/Ga2O3 superlattices." Applied Physics Letters 115.9 (2019): 092105.
4. Cheng, Zhe, et al. "Thermal Transport across Ion-Cut Monocrystalline β-Ga2O3 Thin Films and Bonded β-Ga2O3-SiC Interfaces, ACS applied materials & interfaces, 12(40), 44943-44951.
1. Integration of high thermal conductivity substrates with Ga2O3 for thermal management
2. Thermal conduction in Ga2O3 nanostructures.
Selected Publications:
1. Cheng, Zhe, et al. "Thermal conductance across β-Ga2O3-diamond van der Waals heterogeneous interfaces." APL Materials 7.3 (2019): 031118.
2. Cheng, Zhe, et al. "Integration of polycrystalline Ga2O3 on diamond for thermal management." Applied Physics Letters116.6 (2020): 062105.
3. Cheng, Zhe, et al. "Significantly reduced thermal conductivity in β-(Al0. 1Ga0. 9) 2O3/Ga2O3 superlattices." Applied Physics Letters 115.9 (2019): 092105.
4. Cheng, Zhe, et al. "Thermal Transport across Ion-Cut Monocrystalline β-Ga2O3 Thin Films and Bonded β-Ga2O3-SiC Interfaces, ACS applied materials & interfaces, 12(40), 44943-44951.
Georgia Tech: DOD Air Force Office of Scientific Research (AFOSR) memristor MURI (2017-2018)
1. TDTR thermal measurements on oxides for applications of neuromorphic computing (memristors)
2. Nb2O5 thermal conductivity.
Selected Publications:
1. Cheng, Zhe, et al. "Diffuson-driven ultralow thermal conductivity in amorphous N b 2 O 5 thin films." Physical Review Materials 3.2 (2019): 025002.
1. TDTR thermal measurements on oxides for applications of neuromorphic computing (memristors)
2. Nb2O5 thermal conductivity.
Selected Publications:
1. Cheng, Zhe, et al. "Diffuson-driven ultralow thermal conductivity in amorphous N b 2 O 5 thin films." Physical Review Materials 3.2 (2019): 025002.
Georgia Tech: DOD DARPA Round Robin diamond project (2015-2017)
1. Two years’ TDTR Round Robin thermal measurements on CVD diamond with five thermal teams (three Raman and two TDTR). Accurate thermal measurements on CVD diamond are very challenging!
2. Understand 3D anisotropic (non-homogeneous) thermal conductivity of CVD diamond
3. Develop GaN-on-diamond technique for high-power and high-frequency applications via directly diamond growth on GaN and room-temperature wafer bonding technique. Some collaborators launched a startup to commercialize GaN-on-diamond techniques for applications of satellite communications. (See Akash Systems)
Selected Publications:
1. Cheng, Zhe, et al. "Probing growth-induced anisotropic thermal transport in high-quality cvd diamond membranes by multifrequency and multiple-spot-size time-domain thermoreflectance." ACS applied materials & interfaces 10.5 (2018): 4808-4815.
2. Cheng, Zhe, et al. "Thermal rectification in thin films driven by gradient grain microstructure." Journal of Applied Physics123.9 (2018): 095114.
3. Cheng, Zhe, et al. "Probing local thermal conductivity variations in CVD diamond with large grains by time-domain thermoreflectance." International Heat Transfer Conference Digital Library. Begel House Inc., 2018.
4. Anaya, J., et al. "Simultaneous determination of the lattice thermal conductivity and grain/grain thermal resistance in polycrystalline diamond." Acta Materialia 139 (2017): 215-225.
1. Two years’ TDTR Round Robin thermal measurements on CVD diamond with five thermal teams (three Raman and two TDTR). Accurate thermal measurements on CVD diamond are very challenging!
2. Understand 3D anisotropic (non-homogeneous) thermal conductivity of CVD diamond
3. Develop GaN-on-diamond technique for high-power and high-frequency applications via directly diamond growth on GaN and room-temperature wafer bonding technique. Some collaborators launched a startup to commercialize GaN-on-diamond techniques for applications of satellite communications. (See Akash Systems)
Selected Publications:
1. Cheng, Zhe, et al. "Probing growth-induced anisotropic thermal transport in high-quality cvd diamond membranes by multifrequency and multiple-spot-size time-domain thermoreflectance." ACS applied materials & interfaces 10.5 (2018): 4808-4815.
2. Cheng, Zhe, et al. "Thermal rectification in thin films driven by gradient grain microstructure." Journal of Applied Physics123.9 (2018): 095114.
3. Cheng, Zhe, et al. "Probing local thermal conductivity variations in CVD diamond with large grains by time-domain thermoreflectance." International Heat Transfer Conference Digital Library. Begel House Inc., 2018.
4. Anaya, J., et al. "Simultaneous determination of the lattice thermal conductivity and grain/grain thermal resistance in polycrystalline diamond." Acta Materialia 139 (2017): 215-225.
Main Experimental Skills:
Time-domain thermoreflectance (TDTR)
Ultra-sensitive thermometry and calorimetry
Photo-acoustic technique (PA)
Collaborators
Prof. Hiroshi Amano (Nagoya U)
Prof. Mark Goorsky (UCLA)
Prof. Asif Khan (USC)
Prof. Paul Braun (UIUC)
Prof. Patrick Hopkins (UVA)
Prof. Tengfei Luo (Notre Dame)
Prof. Zhiting Tian (Cornell)
Prof. Huili Grace Xing (Cornell)
Prof. Alan Doolittle (Gatech)
Prof. Tianli Feng (University of Utah)
Dr. Juan Carlos Idrobo (Oak Ridge NL)
Prof. Xiaoqing Pan (UC Irvine)
Prof. Tadatomo Suga (Tokyo U)
Dr. Marko Tadjer (NRL)
Dr. Karl Hobart (NRL)
Dr. Firooz Faili (Element Six)
Dr. Xu Yang (Nagoya U)
Prof. Mark Goorsky (UCLA)
Prof. Asif Khan (USC)
Prof. Paul Braun (UIUC)
Prof. Patrick Hopkins (UVA)
Prof. Tengfei Luo (Notre Dame)
Prof. Zhiting Tian (Cornell)
Prof. Huili Grace Xing (Cornell)
Prof. Alan Doolittle (Gatech)
Prof. Tianli Feng (University of Utah)
Dr. Juan Carlos Idrobo (Oak Ridge NL)
Prof. Xiaoqing Pan (UC Irvine)
Prof. Tadatomo Suga (Tokyo U)
Dr. Marko Tadjer (NRL)
Dr. Karl Hobart (NRL)
Dr. Firooz Faili (Element Six)
Dr. Xu Yang (Nagoya U)
