横方向成長によるSi基板上のInPヘテロエピタキシーに関する研究

University of Tokyo (東京大学

Studies of High Quality InP Layers Heteroepitaxially Grown on Si Substrates by Epitaxial Lateral Overgrowth

報告番号: 甲11825 ; 学位授与年月日: 1996-03-29 ; 学位の種別: 課程博士 ; 学位の種類: 博士(工学) ; 学位記番号: 博工第3623号 ; 研究科・専攻: 工学系研究科電子工学専

Effect of crystallization of Ni catalyst on direct precipitation of multilayer graphene using W capping layer

In recent years, graphene growth technology has been greatly progressed, and it is possible to grow graphene with millimeter-size single crystals using metal-catalysis CVD. However, the transfer process is unavoidably which largely deteriorates the graphene. We have proposed direct precipitation method of graphene using a W capping layer. The method does not only require a transfer process, but also the introduction of wrinkles will be suppressed by optimizing the cooling rate at the graphene precipitation. The growth conditions such as thickness of amorphous carbon, annealing temperature, cooling rate and crystallinity of Ni catalyst were systematically changed to study the mechanism of the precipitation method using the W cap layer. By the optimization of theconditions, wrinkle-free multilayer graphene with D/G ratio of less than 0.1 were successfully obtained directly on a sapphire substrate

Single-walled carbon nanotube synthesis using Pt catalysts under low ethanol pressure via cold-wall chemical vapor deposition in high vacuum

We study single-walled carbon nanotube (SWCNT) growth from Pt catalysts by a cold-wall chemical vapor deposition (CVD) method in a high vacuum using a nozzle injector for the ethanol gas supply. By optimizing the ethanol pressure, we could grow SWCNTs between 330 and 700 °C, and the optimal ethanol pressure to obtain the highest SWCNT yield was reduced as the growth temperature decreased. Using transmission electron microscopy, Raman spectroscopy and photoluminescence measurements, we determined the diameters and chirality distribution of the SWCNTs and showed that the grown SWCNTs have a narrow chirality distribution and that the diameters of most SWCNTs were below 1.0 nm. In addition, based on the size distribution and the chemical states of Pt catalyst particles, we proposed a growth model of the SWCNTs

Behavior of defects in a-plane GaN films grown by low-angle-incidence microchannel epitaxy (LAIMCE)

The microstructure in a-plane GaN thin films was characterized by transmission electron microscopy. The GaN thin films were grown by metal-organic molecular beam epitaxy (MOMBE) on a GaN/r-plane sapphire template using the low-angle-incidence microchannel epitaxy (LAIMCE) technique, following fabrication of a stripe type mask. The polar direction +c at GaN thin films was determined from the electron diffraction pattern by the relationship between c-axis of sapphire and +c of nitride crystal. It was confirmed that threading dislocations passing through the mask windows penetrate into the overgrown GaN layer, running straight up to the Lop surface without bending. Therefore wing regions containing fewer lattice defects are successfully formed. The density of lattice defects is roughly estimated to be around 10(8) cm(-2). Stacking faults (SFs) and partial dislocations on the edges of SFs on the basal planes are found to be formed additionally in the wing regions. As GaN islands that have been formed on the mask windows grow first laterally along +c and -c direction, the microstructures in the c and owing regions were predicted to be different from each other. Bur actually, they are almost the same as each other due to the fact that the islands of GaN develop laterally with the a-plane growth process instead of c-plane growth