J. Semicond. > 2017, Volume 38 > Issue 8 > 083002
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SEMICONDUCTOR MATERIALS

Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode

Yuan Xu1, 2, Benkang Chang1, , Xinlong Chen1 and Yunsheng Qian1

+ Author Affiliations

 Corresponding author: Benkang Chang, Email:bkchang@mail.njust.edu.cn

DOI: 10.1088/1674-4926/38/8/083002

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Abstract: We designed two transmission-mode GaAs/AlGaAs photocathodes with different AlxGa1-xAs layers, one has an AlxGa1-xAs layer with the Al component ranging from 0.9 to 0, and the other has a fixed Al component 0.7. Using the first-principle method, we calculated the electronic structure and absorption spectrum of AlxGa1-xAs at x=0, 0.25, 0.5, 0.75 and 1, calculation results suggest that with the increase of the Al component, the band gap of AlxGa1-xAs increases. Then we activated the two samples, and obtained the spectral response curves and quantum efficiency curves; it is found that sample 1 has a better shortwave response and higher quantum efficiency at short wavelengths. Combined with the band structure diagram of the transmission-mode GaAs/AlGaAs photocathode and the fitted performance parameters, we analyze the phenomenon. It is found that the transmission-mode GaAs/AlGaAs photocathode with variable Al component and various doping structure can form a two-stage built-in electric field, which improves the probability of shortwave response photoelectrons escaping to the vacuum. In conclusion, such a structure reduces the influence of back-interface recombination, improves the shortwave response of the transmission-mode photocathode.

Key words: AlxGa1-xAs layer, variable Al component, GaAs/AlGaAs photocathode, quantum efficiency



[1]
Antonova L I, Denissov V P. High-efficiency photocathodes on the NEA-GaAs basis. Appl Surf Sci, 1997, 111(3):237 https://www.researchgate.net/publication/248189918_High-efficiency_photocathodes_on_the_NEA-GaAs_basis
[2]
Zhang Y J, Chang B K, Yang Z, et al. Distribution of carriers in gradient-doping transmission-mode GaAs photocathodes grown by molecular beam epitaxy. Chine Phys B, 2009, 18:4541 doi: 10.1088/1674-1056/18/10/074
[3]
Alley R, Aoyagi H, Clendenin J, et al. The Stanford linear accelerator polarized electron source. Nucl Instrum Methods Phys Res A, 1995, 365(1):1 doi: 10.1016/0168-9002(95)00450-5
[4]
Siggins T, Sinclair C, Bohn C, et al. Performance of a DC GaAs photocathode gun for the Jefferson lab FEL. Nucl Instrum Methods Phys Res A, 2004, 475(1-3):549 https://www.researchgate.net/publication/235678326_Performance_of_a_DC_GaAs_photocathode_gun_for_the_Jefferson_lab_FEL
[5]
Maruyama T, Brachmanna A, Clendenin J E, et al. A very high charge, high polarization gradient-doped strained GaAs photocathode. Nucl Instrum Methods Phys Res A, 2002, 492(1.2):199 http://www.academia.edu/12726532/A_very_high_charge_high_polarization_gradient-doped_strained_GaAs_photocathode
[6]
Baum A W, Spicer W E, Pease R F W, et al. Negative electron affinity photocathodes as high-performance electron sources. Part 1:achievement of ultrahigh brightness from an NEA photocathode. Proc SPIE, 1995, 2522:208 doi: 10.1117/12.221575
[7]
Antypas G A, Edgecumbe J. Glass-sealed GaAs-AlGaAs transmission photocathode. Appl Phys Lett, 1975, 26(7):371 doi: 10.1063/1.88183
[8]
Zou J J, Yang Z, Qiao J L, et al. On-line measurement system of GaAs photocathodes and its applications. Proc SPIE, 2007, 6782:67823D doi: 10.1117/12.745945
[9]
Feng C, Zhang Y J, Qian Y S. Theoretical revision of quantum efficiency formula for thin AlGaAs/GaAs photocathodes. Proc SPIE, 2014, 9270:92701F doi: 10.1117/12.2071392
[10]
Maruyama T, Prepost R, Garwin E L, et al. Enhanced electron spin polarization in photoemission from thin GaAs. Appl Phys Let, 1989, 55:1686 doi: 10.1063/1.102236
[11]
Chen X L, Y J Zhang, Chang B K, et al. Research on quantum efficiency of reflection-mode GaAs photocathode with thin emission layer. Opt Commun, 2013, 287:35 doi: 10.1016/j.optcom.2012.09.030
[12]
Chen X L, Zhao J, Chang B K, et al. Comparison between exponential-doping reflection-mode GaAlAs and GaAs photocathodes. Acta Phys Sin, 2013, 62(3):037303 https://www.researchgate.net/publication/286575535_Comparison_between_exponential-doping_reflection-mode_GaAlAs_and_GaAs_photocathodes
[13]
Yang Z, Zou J J, Chang B K, et al. Research on the optimal thickness of transmission-mode exponential-doping GaAs photocathode. Acta Phys Sin, 2010, 59(6):4290(in Chinese) https://www.researchgate.net/publication/286546718_Research_on_the_optimal_thickness_of_transmission-mode_exponential-doping_GaAs_photocathode
[14]
Zhao J, Chang B K, Xiong Y J, et al. Influence of the active layer on exponential-doping Ga1-xAlxAs/GaAs photocathode performances. Chin J Electron Dev, 2011, 34(2):119(in Chinese) https://www.researchgate.net/publication/272609796_Research_on_Optical_Properties_of_Ga1-xAlxN_with_Different_Al_Component
[15]
Zou J J, Gao P, Yang Z, et al. Influence of active-layer thickness on reflection-mode GaAs photocathode. Acta Photon Sin, 2008, 37(6):1112(in Chinese) https://www.researchgate.net/publication/286546559_Influence_of_active-layer_thickness_on_reflection-mode_gaas_photocathode
[16]
Zhang Y J, Niu J, Zhao J, et al. Influence of exponential-doping structure on photoemission capability of transmission-mode GaAs photocathodes. J Appl Phys, 2010, 108:093108 doi: 10.1063/1.3504193
[17]
Zhang Y J, Niu J, Zhao J, et al. Effect of exponential-doping structure on quantum yield of transmission-mode GaAs photocathodes. Acta Phys Sin, 2011, 60(6):067301(in Chinese) https://www.researchgate.net/publication/286461785_Effect_of_exponential-doping_structure_on_quantum_yield_of_transmission-mode_GaAs_photocathodes
[18]
Romero M T, Cocoletzi G H, Takeuchi N. First principles calculations of the Sc adsorption on Si(001)-c(2×4). Surf Sci, 2012, 606(17/18):1382 https://www.researchgate.net/publication/303775359_Electronic_structures_of_p-type_impurity_in_ZrS2_monolayer
[19]
Kandemir E B, Gönül B, Barkema G T, et al. Modeling of the atomic structure and electronic properties of amorphous GaN1-xAsx. Comp Mater Sci, 2014, 82:100 doi: 10.1016/j.commatsci.2013.09.039
[20]
Hogan C, Paget D, Garreau Y, et al. 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, 2003, 68(20):205313 doi: 10.1103/PhysRevB.68.205313
[21]
Shirley R, Kraft M, Inderwildi O R. Electronic and optical properties of aluminum-doped anatase and rutile TiO2 from ab initio calculations. Phys Rev B, 2010, 81(7):075111 doi: 10.1103/PhysRevB.81.075111
[22]
Kresse G, Hafner J. Ab initio molecular dynamics for liquid metals. Phys Rev B, 1993, 47(1):558(R) doi: 10.1103/PhysRevB.47.558
[23]
Yu X H, Du Y J, Chang B K, et al. Study on the electronic structure and optical properties of different Al constituent Ga1-xAlxAs. Optik, 2013, 124(20):4402 doi: 10.1016/j.ijleo.2013.03.008
[24]
Goldstein B. LEED-Auger characterization of GaAs during activation to negative electron affinity by the adsorption of Cs and O. Surf Sci, 1975, 47(1):143 doi: 10.1016/0039-6028(75)90280-0
[25]
Hutchby J A, Fudurich R L. Theoretical optimization and parametric study of n-on-p AlxGa1-xAs-GaAs graded band-gap solar cell. J Appl Phys, 1976, 47(7):3152 doi: 10.1063/1.323109
[26]
Chen X L, Zhao J, Chang B K, et al. Photoemission characteristics of (Cs, O) activation exponential-doping Ga0.37Al0.63As photocathodes. J Appl Phys, 2013, 113(21):213105 doi: 10.1063/1.4808291
[27]
Chang B K, Du X Q, Liu L, et al. Automatic recording system of dynamic spectral response and its applications. Proc SPIE, 2003, 5209:209 doi: 10.1117/12.505113
[28]
Zhang Y J, Niu J, Zou J J, et al. Variation of spectral response for exponential-doped transmission-mode GaAs photocathodes in the preparation process. Appl Opt, 2010, 49(20):3935 doi: 10.1364/AO.49.003935
[29]
Chen X L, Zhang Y J, Chang B K, et al. Research on quantum efficiency formula for extended blue transmission-mode GaAlAs/GaAs photocathodes. Optoelectron Adv Mater, 2012, 6(1/2):307 https://www.researchgate.net/publication/286569015_Research_on_quantum_efficiency_formula_for_extended_blue_transmission-mode_GaAlAsGaAs_photocathodes
Fig. 1.  (Color online) Al$_{{x}}$Ga$_{{1-x}}$As calculation model. (a) GaAs model. (b) Al$_{\rm {0.25}}$Ga$_{\rm {0.75}}$As. (c) Al$_{\rm {0.5}}$Ga$_{\rm {0.5}}$As. (d) Al$_{\rm {0.75}}$Ga$_{\rm {0.25}}$As. (e) AlAs.

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Fig. 2.  (Color online) Absorption spectral of Al$_{{x}}$Ga$_{{1-x}}$As calculation models.

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Fig. 3.  Structure diagrams of transmission-mode GaAs photocathodes. (a) Sample 1. (b) Sample 2.

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Fig. 4.  Experimental spectral response curves of two samples.

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Fig. 6.  Band structure diagram of the two samples. (a) Sample 1. (b) Sample 2.

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Fig. 5.  Experimental and fitted quantum efficiency curves of the two samples.

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Table 1.   Formation energy of Al$_{{x}}$Ga$_{{1-x}}$As with different Al component.

Table 2.   Band gap of Al$_{{x}}$Ga$_{{1-x}}$As with different Al component.

Table 3.   Fitted performance parameters of the two samples.
[1]
Antonova L I, Denissov V P. High-efficiency photocathodes on the NEA-GaAs basis. Appl Surf Sci, 1997, 111(3):237 https://www.researchgate.net/publication/248189918_High-efficiency_photocathodes_on_the_NEA-GaAs_basis
[2]
Zhang Y J, Chang B K, Yang Z, et al. Distribution of carriers in gradient-doping transmission-mode GaAs photocathodes grown by molecular beam epitaxy. Chine Phys B, 2009, 18:4541 doi: 10.1088/1674-1056/18/10/074
[3]
Alley R, Aoyagi H, Clendenin J, et al. The Stanford linear accelerator polarized electron source. Nucl Instrum Methods Phys Res A, 1995, 365(1):1 doi: 10.1016/0168-9002(95)00450-5
[4]
Siggins T, Sinclair C, Bohn C, et al. Performance of a DC GaAs photocathode gun for the Jefferson lab FEL. Nucl Instrum Methods Phys Res A, 2004, 475(1-3):549 https://www.researchgate.net/publication/235678326_Performance_of_a_DC_GaAs_photocathode_gun_for_the_Jefferson_lab_FEL
[5]
Maruyama T, Brachmanna A, Clendenin J E, et al. A very high charge, high polarization gradient-doped strained GaAs photocathode. Nucl Instrum Methods Phys Res A, 2002, 492(1.2):199 http://www.academia.edu/12726532/A_very_high_charge_high_polarization_gradient-doped_strained_GaAs_photocathode
[6]
Baum A W, Spicer W E, Pease R F W, et al. Negative electron affinity photocathodes as high-performance electron sources. Part 1:achievement of ultrahigh brightness from an NEA photocathode. Proc SPIE, 1995, 2522:208 doi: 10.1117/12.221575
[7]
Antypas G A, Edgecumbe J. Glass-sealed GaAs-AlGaAs transmission photocathode. Appl Phys Lett, 1975, 26(7):371 doi: 10.1063/1.88183
[8]
Zou J J, Yang Z, Qiao J L, et al. On-line measurement system of GaAs photocathodes and its applications. Proc SPIE, 2007, 6782:67823D doi: 10.1117/12.745945
[9]
Feng C, Zhang Y J, Qian Y S. Theoretical revision of quantum efficiency formula for thin AlGaAs/GaAs photocathodes. Proc SPIE, 2014, 9270:92701F doi: 10.1117/12.2071392
[10]
Maruyama T, Prepost R, Garwin E L, et al. Enhanced electron spin polarization in photoemission from thin GaAs. Appl Phys Let, 1989, 55:1686 doi: 10.1063/1.102236
[11]
Chen X L, Y J Zhang, Chang B K, et al. Research on quantum efficiency of reflection-mode GaAs photocathode with thin emission layer. Opt Commun, 2013, 287:35 doi: 10.1016/j.optcom.2012.09.030
[12]
Chen X L, Zhao J, Chang B K, et al. Comparison between exponential-doping reflection-mode GaAlAs and GaAs photocathodes. Acta Phys Sin, 2013, 62(3):037303 https://www.researchgate.net/publication/286575535_Comparison_between_exponential-doping_reflection-mode_GaAlAs_and_GaAs_photocathodes
[13]
Yang Z, Zou J J, Chang B K, et al. Research on the optimal thickness of transmission-mode exponential-doping GaAs photocathode. Acta Phys Sin, 2010, 59(6):4290(in Chinese) https://www.researchgate.net/publication/286546718_Research_on_the_optimal_thickness_of_transmission-mode_exponential-doping_GaAs_photocathode
[14]
Zhao J, Chang B K, Xiong Y J, et al. Influence of the active layer on exponential-doping Ga1-xAlxAs/GaAs photocathode performances. Chin J Electron Dev, 2011, 34(2):119(in Chinese) https://www.researchgate.net/publication/272609796_Research_on_Optical_Properties_of_Ga1-xAlxN_with_Different_Al_Component
[15]
Zou J J, Gao P, Yang Z, et al. Influence of active-layer thickness on reflection-mode GaAs photocathode. Acta Photon Sin, 2008, 37(6):1112(in Chinese) https://www.researchgate.net/publication/286546559_Influence_of_active-layer_thickness_on_reflection-mode_gaas_photocathode
[16]
Zhang Y J, Niu J, Zhao J, et al. Influence of exponential-doping structure on photoemission capability of transmission-mode GaAs photocathodes. J Appl Phys, 2010, 108:093108 doi: 10.1063/1.3504193
[17]
Zhang Y J, Niu J, Zhao J, et al. Effect of exponential-doping structure on quantum yield of transmission-mode GaAs photocathodes. Acta Phys Sin, 2011, 60(6):067301(in Chinese) https://www.researchgate.net/publication/286461785_Effect_of_exponential-doping_structure_on_quantum_yield_of_transmission-mode_GaAs_photocathodes
[18]
Romero M T, Cocoletzi G H, Takeuchi N. First principles calculations of the Sc adsorption on Si(001)-c(2×4). Surf Sci, 2012, 606(17/18):1382 https://www.researchgate.net/publication/303775359_Electronic_structures_of_p-type_impurity_in_ZrS2_monolayer
[19]
Kandemir E B, Gönül B, Barkema G T, et al. Modeling of the atomic structure and electronic properties of amorphous GaN1-xAsx. Comp Mater Sci, 2014, 82:100 doi: 10.1016/j.commatsci.2013.09.039
[20]
Hogan C, Paget D, Garreau Y, et al. 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, 2003, 68(20):205313 doi: 10.1103/PhysRevB.68.205313
[21]
Shirley R, Kraft M, Inderwildi O R. Electronic and optical properties of aluminum-doped anatase and rutile TiO2 from ab initio calculations. Phys Rev B, 2010, 81(7):075111 doi: 10.1103/PhysRevB.81.075111
[22]
Kresse G, Hafner J. Ab initio molecular dynamics for liquid metals. Phys Rev B, 1993, 47(1):558(R) doi: 10.1103/PhysRevB.47.558
[23]
Yu X H, Du Y J, Chang B K, et al. Study on the electronic structure and optical properties of different Al constituent Ga1-xAlxAs. Optik, 2013, 124(20):4402 doi: 10.1016/j.ijleo.2013.03.008
[24]
Goldstein B. LEED-Auger characterization of GaAs during activation to negative electron affinity by the adsorption of Cs and O. Surf Sci, 1975, 47(1):143 doi: 10.1016/0039-6028(75)90280-0
[25]
Hutchby J A, Fudurich R L. Theoretical optimization and parametric study of n-on-p AlxGa1-xAs-GaAs graded band-gap solar cell. J Appl Phys, 1976, 47(7):3152 doi: 10.1063/1.323109
[26]
Chen X L, Zhao J, Chang B K, et al. Photoemission characteristics of (Cs, O) activation exponential-doping Ga0.37Al0.63As photocathodes. J Appl Phys, 2013, 113(21):213105 doi: 10.1063/1.4808291
[27]
Chang B K, Du X Q, Liu L, et al. Automatic recording system of dynamic spectral response and its applications. Proc SPIE, 2003, 5209:209 doi: 10.1117/12.505113
[28]
Zhang Y J, Niu J, Zou J J, et al. Variation of spectral response for exponential-doped transmission-mode GaAs photocathodes in the preparation process. Appl Opt, 2010, 49(20):3935 doi: 10.1364/AO.49.003935
[29]
Chen X L, Zhang Y J, Chang B K, et al. Research on quantum efficiency formula for extended blue transmission-mode GaAlAs/GaAs photocathodes. Optoelectron Adv Mater, 2012, 6(1/2):307 https://www.researchgate.net/publication/286569015_Research_on_quantum_efficiency_formula_for_extended_blue_transmission-mode_GaAlAsGaAs_photocathodes

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    Received: 07 October 2016 Revised: 08 February 2017 Online: Published: 01 August 2017

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      Article Navigation >  Journal of Semiconductors  > 2017  >  38(8): 083002
      Yuan Xu, Benkang Chang, Xinlong Chen, Yunsheng Qian. Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode[J]. Journal of Semiconductors, 2017, 38(8): 083002. doi: 10.1088/1674-4926/38/8/083002 ****Y Xu, B K Chang, X L Chen, Y S Qian. Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode[J]. J. Semicond., 2017, 38(8): 083002. doi: 10.1088/1674-4926/38/8/083002.
      Citation:
      Yuan Xu, Benkang Chang, Xinlong Chen, Yunsheng Qian. Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode[J]. Journal of Semiconductors, 2017, 38(8): 083002. doi: 10.1088/1674-4926/38/8/083002 ****
      Y Xu, B K Chang, X L Chen, Y S Qian. Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode[J]. J. Semicond., 2017, 38(8): 083002. doi: 10.1088/1674-4926/38/8/083002.
      shu

      Comparative study on the influence of Al component at GaAlAs layer for GaAs/AlGaAs photocathode

      DOI: 10.1088/1674-4926/38/8/083002
      • 1.

        School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China

      • 2.

        School of Electronics and Electrical Engineering, Nanyang Institute of Technology, Nanyang 473004, China

      Funds:

      Project supported by the National Natural Science Foundation of China (Nos. 91433108, 61301023)

      the National Natural Science Foundation of China 61301023

      the National Natural Science Foundation of China 91433108

      More Information
      • Corresponding author: Benkang Chang, Email:bkchang@mail.njust.edu.cn
      • Received Date: 2016-10-07
      • Revised Date: 2017-02-08
      • Published Date: 2017-08-01

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