STM Study on Adsorption Structures of Cs on the As-Terminated GaAs(001) (2×4) Surface by Alternating Supply of Cs and O2

Masayuki HIRAO  Daichi YAMANAKA  Takanori YAZAKI  Jun OSAKO  Hokuto IIJIMA  Takao SHIOKAWA  Hikota AKIMOTO  Takashi MEGURO  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E99-C    No.3    pp.376-380
Publication Date: 2016/03/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E99.C.376
Type of Manuscript: Special Section PAPER (Special Section on Progress towards System Nanotechnology)
Category: 
Keyword: 
work function,  gallium arsenide,  negative electron,  affinity,  photoemission,  photocathode,  scanning tunneling microscope,  

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Summary: 
Negative electron affinity (NEA) surfaces can be formed by alternating supply of alkali metals (e.g. Cs, Rb, K) and oxygen on semiconductor surfaces. We have studied adsorption structures of Cs on an As-terminated (2×4) (001) GaAs surface using scanning tunneling microscopy (STM). We found that the initial adsorption of Cs atoms occurs around the step sites in the form of Cs clusters and that the size of clusters is reduced by successive exposure to O2, indicating that As-terminated (2×4) surfaces are relatively stable compared to Ga-terminated surfaces and are not broken by the Cs clusters adsorption.