Skip to main content
SpringerLink
Log in

Cs and Cs/O adsorption mechanism on GaN nanowires photocathode

  • Original Paper
  • Published:
Journal of Materials Science Aims and scope Submit manuscript

Abstract

We have investigated the stability and electronic properties of GaN nanowires photocathode based on first-principle calculations. The most stable adsorption configuration of Cs adatoms on the (001) surface of [001]-oriented GaN nanowires changes accordingly as Cs coverage increases. The work function of Cs-only-covered surface falls off with increasing Cs coverage. For the nanowire surface covered with either excessive or minor Cs coverage, the work function surprisingly increases slightly after O activation; however, for Cs coverage of 0.5 (monolayer) ML and 0.75 ML, O activation process still works for the nanowires photocathode. A downward band bending region is formed after Cs adsorption and will further bend downward after O adsorption only for models with Cs coverage of 0.5 ML and 0.75 ML. The optimized atomic ratio of Cs/O is 3:1. The diversification of the band structures is mainly attributed to the orbital hybridization between Cs-5 s, Cs-5p, O-2p states and Ga-4 s, N-2p states.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9

Similar content being viewed by others

References

  1. Uchiyama S, Takagi Y, Niigaki M, Kan H, Kondoh H (2005) GaN-based photocathodes with extremely high quantum efficiency. Appl Phys Lett 86:103511

    Article  Google Scholar 

  2. Wang X, Chang B, Ren L, Gao P (2011) Influence of the p-type doping concentration on reflection-mode GaN photocathode. Appl Phys Lett 98:082109

    Article  Google Scholar 

  3. Nishitani T, Honda Y, Amano H (2015) Photocathode electron beam sources using GaN and InGaN with NEA surface. Proc SPIE Int Soc Opt Eng 9363:93630T

    Google Scholar 

  4. Hao G, Zhang Y, Jin M, Feng C, Chen X, Chang B (2015) The effect of surface cleaning on quantum efficiency in AlGaN photocathode. Appl Surf Sci 324:590–593

    Article  Google Scholar 

  5. Wang H, Qian Y, Du Y, Xu Y, Lu L, Chang B (2014) Resolution characteristics for reflection-mode exponential-doping GaN photocathode. Appl Opt 53:335–340

    Article  Google Scholar 

  6. Shen Y, Chen L, Zhang S, Qian Y (2015) Quantum efficiency decay mechanism of NEA GaN photocathode: a first-principles research. Chin Opt Lett 13:100401

    Article  Google Scholar 

  7. Guo X, Wang X, Chang B, Zhang Y, Gao P (2010) High quantum efficiency of depth grade doping negative-electron-affinity GaN photocathode. Appl Phys Lett 97:063104

    Article  Google Scholar 

  8. Sun Y, Liu Z, Pianetta P (2007) Formation of cesium peroxide and cesium superoxide on InP photocathode activated by cesium and oxygen. J Appl Phys 102:074908

    Article  Google Scholar 

  9. Jin X, Cotta AAC, Chen G, N’Diaye AT, Schmid AK, Yamamoto N (2014) Low energy electron microscopy and Auger electron spectroscopy studies of Cs-O activation layer on p-type GaAs photocathode. J Appl Phys 116:174509

    Article  Google Scholar 

  10. Hagan C, Paget D, Garreau Y, Sauvage M, Onida G, Reining L, Chiaradia P, Corradini V (2013) Early stages of cesium adsorption on the As-rich c(2 × 8) reconstruction of GaAs(001): adsorption sites and Cs-induced chemical bonds. Phys Rev B 68:205313

    Article  Google Scholar 

  11. Yu X (2016) A density functional theory research on Cs-O activation process of GaAlAs photocathodes. J Mater Sci 51:8259–8269. doi:10.1007/s10853-016-0103-5

    Article  Google Scholar 

  12. Chen X, Zhao J, Chang B, Yu X, Hao G, Xu Y, Cheng H (2013) Photoemission characteristics of (Cs, O) activation exponential-doping Ga0.37Al0.63As photocathodes. J Appl Phys 113:213105

    Article  Google Scholar 

  13. Xia S, Liu L, Kong Y (2016) Research on quantum efficiency and photoemission characteristics of negative-electron-affinity GaN nanowire arrays photocathode. Opt Quant Electron 48:306

    Article  Google Scholar 

  14. Zou J, Ge X, Zhang Y, Deng W, Zhu Z, Wang W, Peng X, Chen Z, Chang B (2016) Negative electron affinity GaAs wire-array photocathodes. Opt Express 24:256776

    Google Scholar 

  15. Oh I, Kye J, Hwang S (2011) Enhanced photoelectrochemical hydrogen production from silicon nanowire array photocathode. Nano Lett 12:298–302

    Article  Google Scholar 

  16. Northrup JE, Neugebauer J (1996) Theory of GaN(10-10) and (11-20) surfaces. Phys Rev B 53:R10477

    Article  Google Scholar 

  17. Wang Z, Zhang C, Li J, Gao F, Weber WJ (2010) First principles study of electronic properties of gallium nitride nanowires grown along different crystal directions. Comput Mater Sci 50:334–348

    Google Scholar 

  18. Agrawal BK, Pathak A, Agrawal S (2009) Ab initio study of [001] GaN nanowires. J Nanopart Res 11:841–859

    Article  Google Scholar 

  19. Xia S, Liu L, Kong Y, Wang H, Wang M (2016) Study of Cs adsorption on (100) surface of [001]-oriented GaN nanowires: a first principle research. Appl Surf Sci 387:1110–1115

    Article  Google Scholar 

  20. Xia S, Liu L, Kong Y, Wang M (2016) Uniaxial strain effects on the optoelectronic properties of GaN nanowires. Supperlattices Microstruct 97:327–334

    Article  Google Scholar 

  21. Kempisty P, Strak P, Krukowski S (2011) Ab initio determination of atomic structure and energy of surface states of bare and hydrogen covered GaN (0001) surface—existence of the Surface States Stark Effect (SSSE). Surf Sci 605:695–713

    Article  Google Scholar 

  22. Perdew J, Burke K, Ernzerhof M (1996) Erratum: generalized gradient approximation made simple. Phys Rev Lett 77:3865–3868

    Article  Google Scholar 

  23. Kresse G, Hafner J (1993) Ab initio molecular dynamics for liquid metals. Phys Rev B 47:558–561

    Article  Google Scholar 

  24. Perdew J, Zunger A (1981) Self-interaction correction to density-functional approximations for many-electron systems. Phys Rev B 23:5048–5079

    Article  Google Scholar 

  25. Zhang Y, Fang DQ, Zhang SL, Huang R, Wen YH (2016) Structural and electronic properties of ZnO/GaN heterostructured nanowires from first-principles study. Phys Chem Chem Phys 18:3097

    Article  Google Scholar 

  26. Kioseoglou J, Pavloudis Th, Kehahias Th, Komninou Ph, Karakostas Th, Latham CD, Rayson MJ, Briddon PR, Eickhoff M (2015) Structural and electronic properties of GaN nanowires with embedded InxGa1 − xN nanodisks. J Appl Phys 118:034301

    Article  Google Scholar 

  27. Tracy JC (1972) Structural influences on adsorption energy. II. CO on Ni(100). J Chem Phys 56:2736–2747

    Article  Google Scholar 

  28. Cui Z, Ke X, Li E, Liu T (2016) Electronic and optical properties of titanium-doped GaN nanowires. Mater Des 96:409–415

    Google Scholar 

  29. Yang M, Chang B, Wang M (2015) Cesium, oxygen coadsorption on AlGaN(0001) surface: experimental research and ab initio calculations. J Mater Sci Mater Electron 26:2181–2188

    Article  Google Scholar 

  30. Du Y, Chang B, Wang X, Zhang J, Li B, Wang M (2012) Theoretical study of Cs adsorption on GaN(0001) surface. Appl Surf Sci 258:7425–7429

    Article  Google Scholar 

  31. Rosa AL, Neugebauer J (2006) Ferromagnetism in Cu-doped ZnO from first-principles theory. Phys Rev B 73:205346

    Article  Google Scholar 

  32. Li WX, Stampfl C, Scheffler M (2002) Oxygen adsorption on Ag(111): a density-functional theory investigation. Phys Rev B 65:075407

    Article  Google Scholar 

  33. Fu N, Li E, Cui Z, Ma D, Wang W, Zhang Y, Song S, Lin J (2014) The electronic properties of phosphorus-doped GaN nanowires from first-principle calculations. J Alloys Compd 596:92–97

    Article  Google Scholar 

  34. Wang Z, Li J, Gao F, Weber WJ (2010) Codoping of magnesium with oxygen in gallium nitride nanowires. Appl Phys Lett 96:103112

    Article  Google Scholar 

  35. Carter DJ, Stampfl C (2009) Atomic and electronic structure of single and multiple vacancies in GaN nanowires from first-principles. Phys Rev B 79:195302

    Article  Google Scholar 

  36. Garza AJ, Scuseria GE (2016) Predicting band gaps with hybrid density functionals. J Phys Chem Lett 7:4165–4170

    Article  Google Scholar 

Download references

Acknowledgements

We would like to appreciate Meishan Wang of Ludong University for the first-principle calculations. This work is supported by the Natural Science Foundation of Jiangsu Province-China (Grant No. BK20130767), the Fundamental Research Funds for the Central Universities-China (Grant No. 30916011206) and the Six Talent Peaks Project in Jiangsu Province-China (Grant No. 2015-XCL-008).

Author information

Authors and Affiliations

  1. Department of Optoelectronic Technology, School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, People’s Republic of China

    Sihao Xia, Lei Liu, Yu Diao & Yike Kong

Authors
  1. Sihao Xia
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Lei Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Yu Diao
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Yike Kong
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Lei Liu.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary material 1 (DOC 1129 kb)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Xia, S., Liu, L., Diao, Y. et al. Cs and Cs/O adsorption mechanism on GaN nanowires photocathode. J Mater Sci 52, 5661–5671 (2017). https://doi.org/10.1007/s10853-017-0801-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10853-017-0801-7

Keywords

Search

Navigation