1. Effects of graded band-gap structures on spectral response of AlGaAs/GaAs photocathodes
- Author
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Benkang Chang, Wenjuan Deng, Jijun Zou, Xincun Peng, Shaotao Jiang, and Yijun Zhang
- Subjects
medicine.medical_specialty ,Materials science ,business.industry ,Band gap ,Materials Science (miscellaneous) ,Industrial and Manufacturing Engineering ,Cathode ,Particle detector ,Spectral imaging ,law.invention ,Wavelength ,Optics ,law ,Electric field ,medicine ,Optoelectronics ,Business and International Management ,business ,Layer (electronics) ,Electron-beam lithography - Abstract
The effects of AlGaAs/GaAs layer thickness and Al composition range on the spectral response and integral sensitivities of reflection-mode graded band-gap AlGaAs/GaAs photocathodes have been investigated and simulated. The experimental results demonstrate that the spectral response over the wavelength region of interest for graded band-gap photocathodes is greater than that for uniform band-gap cathodes, and the increase in long-wavelength response is more pronounced. These results can be attributed to the built-in electric field in the graded band-gap AlGaAs layer. We established a spectral response model of graded band-gap photocathodes based on the numerical solution of coupled Poisson and continuity equations. According to the model, we calculated the theoretical spectral response and sensitivities of graded band-gap cathodes, and found the optimum Al(x)Ga(1-x)As layer thicknesses are 6, 10, 16, and 22 μm for the reflection-mode cathodes with linearly graded Al composition x ranges of 0 to 0.1, 0.2, 0.3, and 0.4, respectively.
- Published
- 2015
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