Abstract

The aim of this study is to analyze the decaying and recovering mechanism of the quantum efficiency for reflection-mode GaN NEA photocathode. One kind of reflection-mode GaN NEA photocathode is designed and grown in the laboratory. The quantum efficiency curves are obtained immediately and six hours later after the sample is fully activated, the quantum efficiency data at different wavelengths are acquired according to the two different quantum efficiency curves, Through the analysis of experiment result, the inner factors resulting in quantum efficiency decaying are discussed. Taking the factors into consideration, the method of supplementing Cs is applied in recovering the quantum efficiency, the quantum efficiency can be partly recovered. The reason that the quantum efficiency can not be completely recorvered is also anylized.

Keywords:

Negative electron affinity, quantum efficiency, reflection-mode NEA,

References

1. Allen, G.A., 1971. The performance of negative electron affinity photocathode. J. Phys. D Appl. Phys., 4: 308-317.
   CrossRef    
2. Antypas, G.A., L.W. James and J.J. Uebbing, 1970. Operation of III-Vsemiconductor photocathodes in the semitransparent mode. J. Appl. Phys., 41(7): 2888-2894.
   CrossRef    
3. Ettenberg, M., G.H. Olsen and C.J. Nuese, 1976. Effect of gas-phase stoichiometry on the minority-carrier diffusion length in vapor-grown GaAs. Appl. Phys. Lett., 29(3): 141-142.
   CrossRef    
4. James, L.W., 1974. Calculation of the minority-carrier confinement properties of III-Vsemiconductor heterojunctions (applied to transmission-mode photocathodes). J. Appl. Phys., 45(3): 1326-1335.
   CrossRef    
5. Liu, Y.Z., J.L. Moll and W.E. Spicer, 1970. Quantum yield of GaAs semitransparent photocathodes. Appl. Phys. Lett., 17(2): 60-62.
   CrossRef    
6. Machuca, F., Z. Liu, Y. Sun, P. Pianetta, W.E. Spicer and R.F.W. Pearse, 2002. Role of oxygen in semiconductor negative electron affinity photocathodes. J. Vacuum Sci. Technol. B, 20(6): 2721-2725.
   CrossRef    
7. Su, C.Y., I. Lindau and W.E. Spicer, 1982. Photoemission studies of the oxidation of Cs identification of the multiple structures of oxygen species. Chem. Phys. Lett., 87(6): 523-527.
   CrossRef    
8. Terekhov, A.S. and D.A. Orlov, 1995. Photoelectron thermalization near the unpinned surface of GaAs (Cs,O) photocathode. Proceeding of the SPIE, 2550: 157-163.
   CrossRef    
9. Vergara, G., A.H. Gómez and W.E. Spicer, 1995. Escape probability for negative electron affinity photocathodes: calculations compared to experiments. Proceeding of the SPIE, 2550: 142-156.
   CrossRef    
10. Wada, T., T. Nitta and T. Nomura, 1990. Influence of exposure to CO,CO2 and H2O on the stability of GaAs photocathodes. Japanese J. Appl. Phys., 29(10): 2087-209.
    CrossRef    

Competing interests

The authors have no competing interests.

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The authors have no competing interests.