Growth and Characterization of Nanometer-Scale GaAs, AlGaAs and GaAs/InAs Wires

Kenji HIRUMA  Hisaya MURAKOSHI  Masamitsu YAZAWA  Kensuke OGAWA  Satoru FUKUHARA  Masataka SHIRAI  Toshio KATSUYAMA  

IEICE TRANSACTIONS on Electronics   Vol.E77-C   No.9   pp.1420-1425
Publication Date: 1994/09/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Heterostructure Devices and Epitaxial Growth Techniques)
GaAs,  InAs,  quantum wire,  whisker,  STM,  

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Ultrathin GaAs, AlGaAs and GaAs/InAs wire crystals (whiskers) as thin as 20-50 nm are grown by organometallic vapor phase epitaxy (OMVPE) using Au as a growth catalyst. It is found that the whisker shape and width can be controlled by adjusting the thickness of the Au deposited on the substrate surface and the substrate temperature duing OMVPE. A new technique employing a scanning tunneling microscope (STM) for controlling the whisker growth position on the substrate surface is described. Photoluminescence spectra from the GaAs whiskers show a blue shift of the luminescene peak energy as the whisker width decreases. The amount of blue shift energy is rather small compared to that calculated by a simple square potential well model. The discrepancy is explained by the cylindrical potential well model including the surface depletion effect. Atomic composition within the portion of 1-20 nm along the AlGaAs and GaAs/InAs whiskers has been analyzed by energy dispersive X-ray analysis in combination with transmission electron microscopy. This shows the exsitence of Au at the tip of the whisker and the composition change occurs over a length of less than 5 nm at the GaAs/InAs heterojunction.