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Autores principales: Carvalho, Stefany P., Fabris, Guilherme S. L., de Brito, Ana Carolina F., de Oliveira, Raphael B., de Oliveira, Wesley Kardex C., Ruano-Merchan, Catalina, Costa, Carlos A. R., Zagonel, Luiz F., Galvao, Douglas, Barcelos, Ingrid D.
Formato: Preprint
Publicado: 2025
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Acceso en línea:https://arxiv.org/abs/2511.00283
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author Carvalho, Stefany P.
Fabris, Guilherme S. L.
de Brito, Ana Carolina F.
de Oliveira, Raphael B.
de Oliveira, Wesley Kardex C.
Ruano-Merchan, Catalina
Costa, Carlos A. R.
Zagonel, Luiz F.
Galvao, Douglas
Barcelos, Ingrid D.
author_facet Carvalho, Stefany P.
Fabris, Guilherme S. L.
de Brito, Ana Carolina F.
de Oliveira, Raphael B.
de Oliveira, Wesley Kardex C.
Ruano-Merchan, Catalina
Costa, Carlos A. R.
Zagonel, Luiz F.
Galvao, Douglas
Barcelos, Ingrid D.
contents We investigate the air-induced degradation of few-layer hafnium diselenide (HfSe$_2$) through combined experimental and theoretical approaches. AFM and SEM reveal the formation of selenium-rich spherical features upon ambient exposure, while EDS confirms Se segregation. \textit{Ab initio} molecular dynamics simulations show that Se atoms migrate to flake edges and that O/O$_2$ exposure leads to selective Hf oxidation, breaking Se--Hf bonds and expelling Se atoms. No stable Se--O bonds are observed, indicating structural reorganization rather than oxidation. These findings emphasize the material's instability in air and the importance of encapsulation for preserving HfSe$_2$ in practical applications. Scanning tunneling spectroscopy confirms the semiconducting character of the nanoparticles, with an electronic bandgap compatible with that of elemental Se. These results highlight the critical role of lattice defects and oxidation dynamics in the degradation process and underscore the need for encapsulation strategies to preserve the integrity of HfSe$_2$-based devices.
format Preprint
id arxiv_https___arxiv_org_abs_2511_00283
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Ambient-Induced Selenium Segregation and Nanoparticle Formation in 2H-HfSe2: An Experimental and Theoretical Study
Carvalho, Stefany P.
Fabris, Guilherme S. L.
de Brito, Ana Carolina F.
de Oliveira, Raphael B.
de Oliveira, Wesley Kardex C.
Ruano-Merchan, Catalina
Costa, Carlos A. R.
Zagonel, Luiz F.
Galvao, Douglas
Barcelos, Ingrid D.
Materials Science
Other Condensed Matter
We investigate the air-induced degradation of few-layer hafnium diselenide (HfSe$_2$) through combined experimental and theoretical approaches. AFM and SEM reveal the formation of selenium-rich spherical features upon ambient exposure, while EDS confirms Se segregation. \textit{Ab initio} molecular dynamics simulations show that Se atoms migrate to flake edges and that O/O$_2$ exposure leads to selective Hf oxidation, breaking Se--Hf bonds and expelling Se atoms. No stable Se--O bonds are observed, indicating structural reorganization rather than oxidation. These findings emphasize the material's instability in air and the importance of encapsulation for preserving HfSe$_2$ in practical applications. Scanning tunneling spectroscopy confirms the semiconducting character of the nanoparticles, with an electronic bandgap compatible with that of elemental Se. These results highlight the critical role of lattice defects and oxidation dynamics in the degradation process and underscore the need for encapsulation strategies to preserve the integrity of HfSe$_2$-based devices.
title Ambient-Induced Selenium Segregation and Nanoparticle Formation in 2H-HfSe2: An Experimental and Theoretical Study
topic Materials Science
Other Condensed Matter
url https://arxiv.org/abs/2511.00283