2025
Effect 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 shapeGaN
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. 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 defectsModulusNucleation study of AlN crystal growth on 6H-SiC substrates using the MOCVD
Lu Z, Wang Y, Wang L, Xu Y, Liu Y, Xu K. Nucleation study of AlN crystal growth on 6H-SiC substrates using the MOCVD. Applied Physics Letters 2024, 125: 242101. DOI: 10.1063/5.0238459.Peer-Reviewed Original ResearchFormation energyNucleation morphologyAlN crystal growthCrystal growthMolecular dynamics simulationsMetal organic chemical vapor deposition technologyFilm growth processIsland growth modeAlN thin filmsChemical vapor deposition technologyN atomsThin film growth processAdsorption capacityVapor deposition technologyStronger adsorption capacityAtomic structureAdsorption energyAl atomsDynamics simulationsThin filmsGrowth modeHexagonal AlNDeposition technologyAlNStacking faultsImproved surface morphology and reduced V-pits density of lattice-matched AlInN films grown by atmospheric pressure metalorganic chemical vapor deposition
Fan S, Ikeda M, Zhang B, Li Z, Su X, Liu Z, Xu K. Improved surface morphology and reduced V-pits density of lattice-matched AlInN films grown by atmospheric pressure metalorganic chemical vapor deposition. Journal Of Alloys And Compounds 2024, 1007: 176406. DOI: 10.1016/j.jallcom.2024.176406.Peer-Reviewed Original ResearchMetalorganic chemical vapor depositionChemical vapor depositionSurface morphologyVapor depositionPressure metalorganic chemical vapor depositionSevere parasitic reactionsAtmospheric pressure metalorganic chemical vapor depositionAtmospheric-pressure metalorganic chemical vapor depositionIn-plane uniformityLow surface roughnessV-pit densityExcellent surface morphologyAtomic force microscopyGaN/AlInN interfacesParasitic reactionsSurface roughnessGrowth temperatureSecond-order reaction modelReduced roughnessFilm thicknessAlInN filmsForce microscopyRoughness valuesCrystalline qualityElectronic devicesOptical characterization of GaN:Eu microcrystals grown by the ammonothermal method
Xie K, Li T, Ren G, Wang L, Lu W, Shen L, Zhou H, Xu K. Optical characterization of GaN:Eu microcrystals grown by the ammonothermal method. Journal Of Alloys And Compounds 2024, 1008: 176776. DOI: 10.1016/j.jallcom.2024.176776.Peer-Reviewed Original ResearchGlow discharge mass spectrometryTime-resolved photoluminescenceLuminescent sitesPhotoluminescence excitationScanning electron microscopyEu3+ ionsExposed crystal facesEnergy transfer processAmmonothermal methodCharacteristic luminescenceLuminescence propertiesWurtzite crystal structureO2- ionsCrystal structureExcitation wavelengthMass spectrometryCrystal facesLuminescenceEu concentrationMicrocrystalsLuminescence peakPhotoluminescenceTransfer processOptical characterizationEu0A multi-trait epigenome-wide association study identified DNA methylation signature of inflammation among men with HIV
Chen J, Hui Q, Titanji B, So-Armah K, Freiberg M, Justice A, Xu K, Zhu X, Gwinn M, Marconi V, Sun Y. A multi-trait epigenome-wide association study identified DNA methylation signature of inflammation among men with HIV. Clinical Epigenetics 2024, 16: 152. PMID: 39488703, PMCID: PMC11531128, DOI: 10.1186/s13148-024-01763-2.Peer-Reviewed Original ResearchConceptsEpigenome-wide association studiesDNA methylationAssociation studiesDNAm sitesDNA methylation sitesAssociated with DNA methylationDNA methylation signaturesInflammatory markersResponse to virusesImmune response to virusesVeterans Aging Cohort StudySignatures of inflammationGenesIdentified sitesAging Cohort StudyInflammation-related genesPathwayPersistent inflammationMale PWHCohort studyExcess morbidityPWHStudy populationInflammationStatistical powerHigh-power AlGaN deep-ultraviolet micro-light-emitting diode displays for maskless photolithography
Feng F, Liu Y, Zhang K, Yang H, Hyun B, Xu K, Kwok H, Liu Z. High-power AlGaN deep-ultraviolet micro-light-emitting diode displays for maskless photolithography. Nature Photonics 2024, 1-8. DOI: 10.1038/s41566-024-01551-7.Peer-Reviewed Original ResearchMicro-light-emitting diodesMicro-LED displayMicro-LEDsMaskless photolithographySuperior light extraction efficiencyPeak external quantum efficiencyLight extraction efficiencyMicro-LED arrayExternal quantum efficiencyElectrical characterizationCircuit driverDeep ultravioletPhotoresist filmSpreading uniformityQuantum efficiencyEmission uniformityPhotolithographySemiconductor industryHeat dispersionMicro-displaysMaximum brightnessReflective layerPhotolithography applicationsOptimal performanceDiodesHBI: a hierarchical Bayesian interaction model to estimate cell-type-specific methylation quantitative trait loci incorporating priors from cell-sorted bisulfite sequencing data
Cheng Y, Cai B, Li H, Zhang X, D’Souza G, Shrestha S, Edmonds A, Meyers J, Fischl M, Kassaye S, Anastos K, Cohen M, Aouizerat B, Xu K, Zhao H. HBI: a hierarchical Bayesian interaction model to estimate cell-type-specific methylation quantitative trait loci incorporating priors from cell-sorted bisulfite sequencing data. Genome Biology 2024, 25: 273. PMID: 39407252, PMCID: PMC11476968, DOI: 10.1186/s13059-024-03411-7.Peer-Reviewed Original ResearchConceptsMethylation quantitative trait lociQuantitative trait lociTrait lociMethylation dataFunctional annotation of genetic variantsAnnotation of genetic variantsGenetic variantsBisulfite sequencing dataEffects of genetic variantsBiologically relevant cell typesDNA methylation levelsCell typesFunctional annotationSequence dataComplex traitsMethylation datasetsRelevant cell typesMeQTLsMethylation levelsMethylation regulatorsReal data analysesLociVariantsMethylationDNAFrequent Cocaine Use is Associated With Larger HIV Latent Reservoir Size
Aouizerat B, Garcia J, Domingues C, Xu K, Quach B, Page G, Konkle-Parker D, Bolivar H, Lahiri C, Golub E, Cohen M, Kassaye S, DeHovitz J, Kuniholm M, Archin N, Tien P, Hancock D, Johnson E. Frequent Cocaine Use is Associated With Larger HIV Latent Reservoir Size. JAIDS Journal Of Acquired Immune Deficiency Syndromes 2024, 97: 156-164. PMID: 39250649, DOI: 10.1097/qai.0000000000003472.Peer-Reviewed Original ResearchHIV latent reservoirImpact of cocaine useCocaine useT cellsAssociated with higher HIV viral loadHigher HIV viral loadSelf-reported cocaine useHIV DNA assaysLatent reservoir sizeRapid HIV progressionVirologically suppressed womenHIV viral loadFrequent cocaine useVirally suppressed PLWHHistory of HIVLatent reservoirAntiretroviral therapyHIV progressionLongitudinal cohort studyViral loadCocaine usersNever usersIntact provirusesCohort studyCD4Dislocation evolution in anisotropic deformation of GaN under nanoindentation
Chen K, Xue M, Chen R, Dong X, Gao X, Wang J, Han S, Song W, Xu K. Dislocation evolution in anisotropic deformation of GaN under nanoindentation. Applied Physics Letters 2024, 125: 142101. DOI: 10.1063/5.0230366.Peer-Reviewed Original ResearchDislocation evolutionShear stressInduced subsurface damageEnergy storage systemSlip system activityDislocation loopsPeierls-Nabarro stressCritical shear stressAbrasive particlesDislocation nucleationDislocation dynamicsPop-inSubsurface damageMulti-functional devicesCompressive stressDevice performanceMolecular dynamicsTransmission electron microscopyWireless communicationDefect evaluationStorage systemSingle crystalsGaN single crystalsRaman spectroscopyGaN wafersGaN-Based Freestanding Micro-LEDs With GHz Bandwidth and Low Efficiency Droop for Visible Light Communication
Huang J, Wang G, Xu H, Xu F, Zhi T, Chen W, Sang Y, Zhang D, Yu J, He H, Xu K, Tian P, Tao T, Liu B, Zhang R. GaN-Based Freestanding Micro-LEDs With GHz Bandwidth and Low Efficiency Droop for Visible Light Communication. IEEE Transactions On Electron Devices 2024, 71: 6826-6830. DOI: 10.1109/ted.2024.3456770.Peer-Reviewed Original ResearchVisible light communicationExternal quantum efficiencyModulation bandwidthQuantum-confined Stark effectQuantum barriersLight communicationMicro-LEDsEfficiency droopFree-space visible light communicationMicro-light-emitting diodesM-diameterM-diameter deviceImproved carrier transportLow efficiency droopData rateFree-spaceGHz bandwidthLight-emitting diodesOptical powerDefect densityCarrier transportBandwidthEnergy-efficient methodCarrier localizationStark effectLeakage current in GaN-on-GaN vertical GaN SBDs grown by HVPE on native GaN substrates
Jin W, Zhang Y, Xia S, Zhu Q, Sun Y, Yi J, Wang J, Xu K. Leakage current in GaN-on-GaN vertical GaN SBDs grown by HVPE on native GaN substrates. AIP Advances 2024, 14: 095118. DOI: 10.1063/5.0208706.Peer-Reviewed Original ResearchSchottky barrier diodesGaN Schottky barrier diodesVertical GaN-on-GaN Schottky barrier diodesPoole–Frenkel emissionNative GaN substratesVertical GaN Schottky barrier diodesGaN substratesBarrier diodesDefect etchingLeakage currentOptimal fabrication processLeakage mechanismFabricated deviceForeign substratesFabrication processEmissionPassive techniquesGrowth and characterization of micro-LED based on GaN substrate.
Wang G, Huang J, Wang Y, Tao T, Zhu X, Wang Z, Li K, Wang Y, Su X, Wang J, Liu B, Cao B, Xu K. Growth and characterization of micro-LED based on GaN substrate. Optics Express 2024, 32: 31463-31472. PMID: 39573280, DOI: 10.1364/oe.529771.Peer-Reviewed Original ResearchExternal quantum efficiencyMicro-LED chipResidual stressDislocation densityMicro-LEDsGaN-based micro-LEDReduced dislocation densityCarrier injectionQuantum efficiencyDislocation phenomenaHigher uniformitySuperior uniformityMicro-LED technologyGaN substratesPit distributionDominant mechanismChipDislocationHigh brightnessUniformityUltra-low-defect homoepitaxial micro-LEDs with enhanced efficiency and monochromaticity for high-PPI AR/MR displays
Liu Y, Wang G, Feng F, Zhanghu M, Yuan Z, Li Z, Xu K, Kwok H, Liu Z. Ultra-low-defect homoepitaxial micro-LEDs with enhanced efficiency and monochromaticity for high-PPI AR/MR displays. PhotoniX 2024, 5: 23. DOI: 10.1186/s43074-024-00137-4.Peer-Reviewed Original ResearchGaN-on-GaNOptoelectronic propertiesEfficiency droop ratioEmission wavelengthMicro-LEDsGaN-on-sapphireCrystal qualityMicro-displaysCm-2High luminanceMicro-display applicationsMicro-LED devicesGaN substratesSapphire substratesDroop ratioEfficiency droopSeries resistanceGallium nitrideEnhanced efficiencyStrong ambient lightArtificial Intelligence Applications in Oral Cancer and Oral Dysplasia
Viet C, Zhang M, Dharmaraj N, Li G, Pearson A, Manon V, Grandhi A, Xu K, Aouizerat B, Young S. Artificial Intelligence Applications in Oral Cancer and Oral Dysplasia. Tissue Engineering Part A 2024, 30: 640-651. PMID: 39041628, PMCID: PMC11564848, DOI: 10.1089/ten.tea.2024.0096.Peer-Reviewed Original ResearchOral squamous cell carcinomaOral epithelial dysplasiaPredictive biomarkersMalignant transformation of oral epithelial dysplasiaOral squamous cell carcinoma outcomesOSCC behaviorTransformation to oral squamous cell carcinomaClinical challengeOral epithelial dysplasia patientsOSCC survivalPrecursors of oral squamous cell carcinomaTumor immune microenvironmentSquamous cell carcinomaImmune cell patternsEpithelial dysplasiaOral dysplasiaImmune microenvironmentCell carcinomaImproved survivalMultiplex immunohistochemistryOral cancerOSCC patientsTreatment responsePoor outcomeDisfiguring treatmentMicrostructure and Properties of NiCrFeBMn Alloy Coating Prepared on 304 Stainless Steel by Using Extreme High-Speed Laser Cladding
Fu F, Xu K, Zeng P, Chen H, Xie Y, Liu M, Gao Z, Wang J. Microstructure and Properties of NiCrFeBMn Alloy Coating Prepared on 304 Stainless Steel by Using Extreme High-Speed Laser Cladding. Integrated Ferroelectrics 2024, 240: 934-941. DOI: 10.1080/10584587.2024.2327930.Peer-Reviewed Original ResearchLaser powerCorrosion resistanceHigh-speed laser claddingProperties of wear resistanceEffects of laser powerLaser cladding coatingLaser cladding techniqueNi-based alloysCladding coatingLaser claddingCladding techniqueWear resistanceAlloy coatingsNi-baseStainless steelCoatingCoating preparationCorrosionPowerSteelCladdingLaserMicrostructureStainlessAlloyStep-edge-guided nucleation and growth mode transition of α-Ga2O3 heteroepitaxy on vicinal sapphire
Hao J, Zhang Y, Zhang Y, Xu K, Han G, Ye J. Step-edge-guided nucleation and growth mode transition of α-Ga2O3 heteroepitaxy on vicinal sapphire. Chinese Physics B 2024, 33: 086104. DOI: 10.1088/1674-1056/ad4ff6.Peer-Reviewed Original ResearchGrowth mode transitionGrowth modeDislocation densityTerrace widthCm-2Epitaxial growth modeIncreased dislocation densityNeighboring nucleiFlat sapphire surfaceTwo-dimensional (2DSurface morphology degradationSubstrate terracesVicinal sapphireMaterial propertiesSurface roughnessTerrace edgesDevice performanceMiscut angleCoherent growthSapphire substratesSemiconductor layerEdge dislocationsHeteroepitaxial layersMode transitionNucleation distanceComparative analysis of microstructure, electrical and optical performance in sidewall etching process for GaN-based green micro-LED
Li X, Su X, Wang G, Chen J, Wang L, Song W, Xu K. Comparative analysis of microstructure, electrical and optical performance in sidewall etching process for GaN-based green micro-LED. Journal Of Physics D 2024, 57: 375108. DOI: 10.1088/1361-6463/ad55f9.Peer-Reviewed Original ResearchKelvin probe force microscopeGeometric phase analysisTransmission electron microscopyExternal quantum efficiencyTime-resolved photoluminescenceInductively coupled plasmaOptical performanceSidewall defectsEvolution of microstructureInductively coupled plasma etchingTetramethylammonium hydroxide treatmentBuild-in electric fieldMicro-LEDsNon-radiative recombination lossesGreen micro-LEDsSemi-polar surfacesSurface lattice relaxationSurface dangling bondsTetramethylammonium hydroxideNon-radiative recombination mechanismsNon-radiative recombination rateChip sizeTetramethylammonium hydroxide solutionForce microscopeEtching process60‐4: Minimal Efficiency Degradation and Elevated Radiometric Power Density of Ultraviolet‐A Micro‐LED with Homoepitaxial Structure
Liu Y, Wang G, Feng F, Li Z, Liu Z, Xu K, Kwok H, Liu Z. 60‐4: Minimal Efficiency Degradation and Elevated Radiometric Power Density of Ultraviolet‐A Micro‐LED with Homoepitaxial Structure. SID Symposium Digest Of Technical Papers 2024, 55: 828-831. DOI: 10.1002/sdtp.17658.Peer-Reviewed Original Research