The Study Of Heterojunction Interfaces Between InN/6H-SiC, InN/GaAs And InN/NiO

200nm-thick high quality InN was grown on6H-SiC substrate by MBE.The FWHMvalue of rocking curve for (002) peak of thick film is only792arc sec. Although thisvalue is not comparable to the high-quality InN obtained on the GaN substrate, it iscomparable, even smaller than that of InN grown on6H-SiC. The valence band offset(VBO) of InN/6H-SiC heterojunction has been directly measured by x-rayphotoelectron spectroscopy. The VBO is determined to be-0.10±0.23eV and theconduction band offset is deduced to be-2.47±0.23eV, indicating that theheterojunction has a type-II band alignment. According to the value we gotten, theband alignment diagram was drawn. The accurate determination of the valence andconduction band offsets is important for applications and analysis of InN/6H-SiCoptoelectronic deviceThrough Indium beam irradiation towards the substrate before growing, highdensity uniform InN nanocolumns were obtained on p-GaAs substrate. Thenanoculomns grew in the VLS mode in the initial stage catalyzed by the liquid stateInxN1-x, after depletion of InxN1-x, it went on growing in1D model, as the density ofthe nanocolumns was too high to form new nucleation site. The sufficient diffusiontime was critical for fabricating high density uniform InN nanocolumns.Theformation of nanocolumns was an effective way to release the strain betweenhexagonal InN(0001) and cubic GaAs (001). Through quantitative analysis of XPSspectra gotten by in-situ measurement, it was found that the InN stoichiometric ratioof all three samples were close to1:1, which revealed that there was no residual metalat the tip of our nanocolumns. No catalyst or residual metal left could keep itselectronic and optical property intact. All three samples showed strong photoluminescence at room temperature. To effectively release the strain and to getwell interface and surface are important for heterojunction optoelectronic devicebased on InN.With the Hall mobility of1.22cm2/V s, the carrier concentration of2.524×1018/cm3p type NiO was gotten by magnetron sputtering.200nm-thick high qualityInN was grown on6H-SiC substrate by MBE. The FWHM value of rocking curve for(002) peak of thick film is only792arc sec. The valence band offset (VBO) ofInN/NiO heterojunction has been directly measured by x-ray photoelectronspectroscopy. A type-Ⅱ band alignment with a VBO of E=-0.38±0.23eV andCBO of E=-3.43±0.23eV is obtained. Comparing with both InN/Si and InN/GaAsheterojunctions with type-Ⅲ band alignment i.e. broken gap, n-InN/p-NiOheterojunction could form p-n junction more easily. According to the value we gotten,the band alignment diagram was drawn. The accurate determination of the valenceand conduction band offsets is important for applications and analysis of InN/NiOoptoelectronic device.Previous to growth, the nitridation process was taken to fabricate thin GaN film onp type GaAs (001) face. For all samples with and without low temperature bufferlayer, nitridation process before the growth could improve the sample surface largely;among the samples which have been nitrided, the samples with low temperaturebuffer layer have smoother surface than samples without. For the sample gottenwithout nitridation, the I-V curve between epytaxy InN and GaAs is linear, norectification characteristic presents. Utilizing nitridation process makes theheterojunction between InN and GaAs formed. And the heterojunction presentsrectification characteristics. The growth conditionr of nitridation process lasting for1hour and utlizing low temperature buffer layer makes the epytaxy InN surface smoothand InN/GaAs heterojunction own good rectification characteristic.