简介：Aone-dimensionalfluidmodelforhomogeneousatmosphericpressurebarrierdischargesinheliumispresentedbyconsiderilagelementaryprocessesofexcitationandionizationincludingametastableatomeffect.Usingthismodelweinvestigatethebehavioursoftheheliummetastableatomsindischargesaswellastheirinfluenceonthedischargecharacteristics.Itisshownthatthemetastableatomswitharelativelyhighconcentrationduringthedischargearemainlyproducedintheactivephaseofthedischargeanddissolvedintheoffphase.Itisalsofoundthatthemetastableatomcollisionscannotonlyprovideseedelectronsfordischargesbutalsoinfluencetheconcentrationofions.Areductionofmatestableatomdensityresultsinadropinthechargedparticledensitiesandcausesaqualitativechangeinthedischargepatterns.

简介：AlONnanolayersaresynthesizedonAlsubstratebytheirradiationofenergeticnitrogenionsusingplasmafocusing.Samplesareexposedtomultiple(5,10,15,20and25)focusshots.Ionenergyandionnumberdensityrangefrom80keVto1.4MeVand5.6×1019m-3to1.3×1019m-3,respectively.Moreover,theefectofcontinuousannealing(473Kand523K)onanAlNsurfacelayersynthesizedwith25focusshotsisalsoexamined.ThemainfeaturesoftheX-raydifraction(XRD)patternswithincreasingfocusshotsare:(i)variationinthecrystallinityofAlNalong(111),(200)and(311)planes,(ii)increasingaveragecrystallitesizeofAlN(111)plane,and(iii)stressrelaxationobservedinAlN(111)and(200)planes.ThecrystallinityofAlNsurfacelayeriscomparativelybetterat473Kannealingtemperature.Abroadeneddifractionpeakrelatedtoanaluminiumoxidephaseshowingweakcrystallinityisobservedfor15focusshotswhilenon-boundedoxidesarepresentinallotherdepositedlayers.RamanandFouriertransforminfraredspectroscopy(FTIR)analysisconfirmthepresenceofAlNandAl2O3forthesurfacelayerannealedat473Ktemperature.RamananalysisshowsthattheoverlappingofAlNandAl2O3resultsinthedevelopmentofresidualstresses.Scanningelectronmicroscope(SEM)resultsdemonstratethattheformationofroundedgrains(rangefrom20nmto200nm)andvariationsintheirmicrostructuresfeaturesdependontheincreasingnumberoffocusshots.Decompositionoflargerclustersintosmalleronesisobserved.