Ke Xu, MD
Professor of PsychiatryCards
About
Research
Overview
Medical Research Interests
Genetics, Behavioral; Mental Disorders
Public Health Interests
Genetics, Genomics, Epigenetics; Mental Health; Substance Use, Addiction
Publications
2025
Hotspot and nonequilibrium thermal transport in AlGaN/GaN FinFET: A coupled electron-phonon Monte Carlo simulation study
Hu B, Wang Z, Xu K, Tang D. Hotspot and nonequilibrium thermal transport in AlGaN/GaN FinFET: A coupled electron-phonon Monte Carlo simulation study. International Journal Of Heat And Mass Transfer 2025, 241: 126679. DOI: 10.1016/j.ijheatmasstransfer.2025.126679.Peer-Reviewed Original ResearchNonequilibrium thermal transportThermal transportAlGaN/GaN FinFETsPolar optical scatteringElectron-phonon scatteringThermal transport processesPrimary phonon modesFirst-principles calculationsSevere self-heating effectPhonon modesStrong nonequilibriumEmission processMonte Carlo simulationsEnergy dissipation processIntermediate stateDissipative processesOptical scatteringSelf-heating effectCarlo simulationsTransport processesDissipation timeScatteringPeak temperature riseCoupling effectComplex transport mechanismsResearch on the epitaxial growth of Power/RF HEMT structures on n-GaN and Fe-doped SI-GaN Free-Standing Substrates by MOCVD
Wang X, Zhang Y, Wang M, Wang J, Xu K. Research on the epitaxial growth of Power/RF HEMT structures on n-GaN and Fe-doped SI-GaN Free-Standing Substrates by MOCVD. Vacuum 2025, 235: 114135. DOI: 10.1016/j.vacuum.2025.114135.Peer-Reviewed Original ResearchMetal organic chemical vapor depositionHigh-electron-mobility transistorsEpitaxial layersTwo-dimensional electron gasAlGaN/GaN high-electron-mobility transistorsEpitaxial growthLow-temperature mobilityGaN channel layerSemi-insulating GaNFree-standing GaN substratesGaN buffer layerRadio frequencyFe impurity concentrationsElectron gasChemical vapor depositionImpurity concentrationHEMT structuresEpitaxial structureDislocation densityN-GaNLow-temperature growthGaN substratesStopper layerChannel layerSurface roughnessPostoperative TIPS Reaction in a Patient With Portal Vein Dysfunction
Du Q, Lan J, Xu K, Niu M. Postoperative TIPS Reaction in a Patient With Portal Vein Dysfunction. Portal Hypertension & Cirrhosis 2025 DOI: 10.1002/poh2.70003.Peer-Reviewed Original ResearchEffect of AlN interlayer thickness on thermal conductances of GaN epilayer and GaN/SiC interface in GaN-on-SiC heterostructures
Wang L, Zhang Z, Su X, Zhou J, Chen J, Li Z, Chang G, Xia S, Yin T, Niu M, Zhu J, Tang D, Xu K. Effect of AlN interlayer thickness on thermal conductances of GaN epilayer and GaN/SiC interface in GaN-on-SiC heterostructures. Applied Surface Science 2025, 686: 162106. DOI: 10.1016/j.apsusc.2024.162106.Peer-Reviewed Original ResearchHigh electron mobility transistorsAlN interlayer thicknessGaN-on-SiCGaN epilayersAlN interlayerPhonon density of statesHeteroepitaxial growth of GaNDensity of statesAtomically smooth interfaceThermal conductivityElectron mobility transistorsTime-domain thermoreflectanceMultilayer structureEnhancement of G′Growth of GaNInterfacial thermal conductanceInterlayer thicknessMetal organic chemical vapor depositionSiC substrateMobility transistorsAlN bufferGrow GaNChemical vapor depositionIsland shapeGaNOn the dependence of internal stress on dislocation inclination pattern in HVPE-GaN substrates
Zhou F, Li Z, Liu M, Qiu Y, Yin T, Xu Y, Zhang Y, Niu M, Cai D, Wang J, Xu K. On the dependence of internal stress on dislocation inclination pattern in HVPE-GaN substrates. Applied Physics Letters 2025, 126: 082101. DOI: 10.1063/5.0255742.Peer-Reviewed Original ResearchInternal stressX-ray topographyDislocation configurationsDislocation patternsHVPE GaN substratesInclination of threading dislocationsTwo-photon excited photoluminescenceCombined Raman spectroscopyDependence of internal stressesRaman spectroscopyX-rayExcited photoluminescenceHydride vapor phase epitaxyVapor phase epitaxyDistribution of internal stressesDislocationInternal stress distributionPerformance of GaN devicesClassical elasticity theoryEpitaxial growthPhase epitaxyGaN substratesGaN devicesStress distributionElasticity theoryOptical properties of Mg-implanted GaN grown on free-standing substrates
Wu W, Pan Y, Gao X, Wang X, Wei S, Sun J, Zeng X, Zheng S, Xu K. Optical properties of Mg-implanted GaN grown on free-standing substrates. Journal Of Physics D 2025, 58: 135101. DOI: 10.1088/1361-6463/ada8bb.Peer-Reviewed Original ResearchGaN:MgGaN thin filmsLuminescence bandThin filmsMetal organic chemical vapor depositionGreen luminescence bandBlue luminescence bandM-plane substrateLow-temperature PL spectraAcceptor energy levelChemical vapor depositionGaN free-standing substrateMg-doped GaNMg-implanted GaNUltraviolet luminescence peakPL spectraC-plane substratesLuminescence peakOptical propertiesEnergy levelsVapor depositionIon implantationAcceptorMgGa acceptorPhotoluminescenceElectron–phonon coupling and thermal transport properties of GaN/AlGaN heterojunction under strain regulation
Chen J, Shan Z, Hu B, Wang Z, Tang D, Xu K. Electron–phonon coupling and thermal transport properties of GaN/AlGaN heterojunction under strain regulation. Physical Chemistry Chemical Physics 2025, 27: 2495-2509. PMID: 39804036, DOI: 10.1039/d4cp03880k.Peer-Reviewed Original ResearchElectron-phonon couplingIn-plane stressesTensile strainThermal transportCompressive strainPhonon frequenciesTwo-dimensional electron gasElectron-phonon coupling phenomenaSemiconductor materialsInterface thermal transportApplication of semiconductor materialsStates of phononsLow-frequency phononsFirst-principles calculationsThermoelectric properties of semiconductor materialsThermal transport propertiesBallistic phonon transportInterference of strainNon-equilibrium stateProperties of semiconductor materialsMigration of electronsThermal transport mechanismsIn-plane strainElectron gasPhonon modesTemperature Dependence of Electrical Properties of Ammonothermal GaN
Shen L, Li T, Ren G, Xie K, Lu W, Zhou H, Xu K. Temperature Dependence of Electrical Properties of Ammonothermal GaN. Physica Status Solidi (a) – Applications And Materials Science 2025 DOI: 10.1002/pssa.202400832.Peer-Reviewed Original ResearchPolar optical phonon scatteringOptical phonon scatteringIonized impurity scatteringImpurity scatteringPhonon scatteringImpurity concentrationScattering mechanismsTemperature dependenceScattering effectsExperimentally measured valuesScatteringAmmonothermal methodLow temperaturesTemperature rangeCalculated valuesRoom temperatureElectrical propertiesMeasured valuesTemperatureGaN.High temperatureImpuritiesGaN
2024
Epigenome-Wide and Methylation Risk Score Analysis of Body Mass Index Among People with HIV
Abi N, Young A, Tiwari P, Chen J, Liu C, Hui Q, So-Armah K, Freiberg M, Justice A, Xu K, Gwinn M, Marconi V, Sun Y. Epigenome-Wide and Methylation Risk Score Analysis of Body Mass Index Among People with HIV. Epigenomes 2024, 8: 46. PMID: 39727808, PMCID: PMC11675887, DOI: 10.3390/epigenomes8040046.Peer-Reviewed Original ResearchMethylation risk scoreBody mass indexReduce cardiometabolic disease riskBody mass index associationsMass indexBody mass index varianceRisk of type 2 diabetesVeterans Aging Cohort StudyEpigenome-wide association studiesAnalysis of body mass indexCardiometabolic disease riskAntiretroviral therapyAging Cohort StudyNon-HIV individualsObesity-related risksEpigenome-wide significant CpG-sitesMale PWHLinear mixed modelsTargeted interventionsType 2 diabetesCohort studyDisease riskRisk scorePWHAssociation studiesNanoindentation mechanical studies of bulk AlN single crystals with different orientations
Zhou H, Chen K, Gao X, Zheng S, Zeng X, Wang C, Wang Y, Pan Y, Xu K. Nanoindentation mechanical studies of bulk AlN single crystals with different orientations. Semiconductor Science And Technology 2024, 40: 015008. DOI: 10.1088/1361-6641/ad98b8.Peer-Reviewed Original ResearchIndentation depthYoung's modulusPhysical vapor transportIncreasing indentation depthIndentation size effectNano-mechanical testingLuminescence quenchingSmall Young's modulusCrystal planesSingle crystalsCrystal substratesRaman spectroscopyMechanical propertiesPanchromatic CL imagesLocal stressAlN single crystalsSurface morphologyMechanism studyAluminum nitrideProperties of AlNSlip regionCrystalIndentationStructural defectsModulus
Clinical Trials
Current Trials
A longitudinal study of the effects of cannabis exposure on neuro-development in adolescents and young adults
HIC ID2000024543RoleSub InvestigatorPrimary Completion Date01/31/2021Recruiting ParticipantsGenderBothAge13 years - 25 years
Academic Achievements & Community Involvement
News
News
- May 20, 2024Source: Journal of Behavioral Medicine
Childhood Adversity, Accelerated GrimAge, and Associated Health Consequences
- December 07, 2023
VA/Yale Researchers Lead Multi-ancestry Study of Genetics of Problematic Alcohol Use
- July 24, 2023Source: Neurobiology of Stress
Greater Stress and Trauma Mediate Race-Related Differences in Epigenetic Age Between Black and White Young Adults in a Community Sample
- March 15, 2022
Alcohol Consumption Changes the Aging Clock
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