Thermal stability of the negative electron affinity condition on cubic boron nitride
作者:
Kian Ping Loh,
Mikka Nishitani-Gamo,
Isao Sakaguchi,
Takashi Taniguchi,
Toshihiro Ando,
期刊:
Applied Physics Letters
(AIP Available online 1998)
卷期:
Volume 72,
issue 23
页码: 3023-3025
ISSN:0003-6951
年代: 1998
DOI:10.1063/1.121528
出版商: AIP
数据来源: AIP
摘要:
We have verified that the condition of negative electron affinity (NEA) exists on hydrogen-terminated polycrystalline cubic boron nitride(c-BN)grown by the high-pressure high-temperature method using ultraviolet photoelectron spectroscopy. The NEA condition is thermally stable to 950 °C. At higher temperatures, the surface reverts to a positive electron affinity condition due to the desorption of surface bound hydrogen. Repeated annealing at high temperatures results in the degradation of the surface crystallinity, which manifests in the growth of a&pgr;→&pgr;*feature attributable tosp2-type bonds. Complete regeneration of initial valence band features and NEA conditions along with the suppression of the&pgr;→&pgr;*features can be achieved by subjecting the surface to atomic hydrogen etching. It is discovered that the He (II)-excited valence band spectra ofc-BNdisplay significant differences between the hydrogen-terminated and hydrogen-free surface. ©1998 American Institute of Physics.
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