Citation: |
Minyou He, Liang Chen, Lingai Su, Lin Yin, Yunsheng Qian. Comparative research on the influence of varied Al component on the active layer of AlGaN photocathode[J]. Journal of Semiconductors, 2017, 38(6): 063004. doi: 10.1088/1674-4926/38/6/063004
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M Y He, L Chen, L G Su, L Yin, Y S Qian. Comparative research on the influence of varied Al component on the active layer of AlGaN photocathode[J]. J. Semicond., 2017, 38(6): 063004. doi: 10.1088/1674-4926/38/6/063004.
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Comparative research on the influence of varied Al component on the active layer of AlGaN photocathode
DOI: 10.1088/1674-4926/38/6/063004
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Abstract
To theoretically research the influence of a varied Al component on the active layer of AlGaN photocathodes, the first principle based on density functional theory is used to calculate the formation energy and band structure of AlxGa1-xN with x at 0, 0.125, 0.25, 0.325, and 0.5. The calculation results show that the formation energy declines along with the Al component rise, while the band gap is increasing with Al component increasing. AlxGa1-x with x at 0, 0.125, 0.25, 0.325, and 0.5 are direct band gap semiconductors, and their absorption coefficient curves have the same variation tendency. For further study, we designed two kinds of reflection-mode AlGaN photocathode samples. Sample 1 has an AlxGa1-x active layer with varied Al component ranging from 0.5 to 0 and decreasing from the bulk to the surface, while sample 2 has an AlxGa1-x active layer with the fixed Al component of 0.25. Using the multi-information measurement system, we measured the spectral response of the activated samples at room temperature. Their photocathode parameters were obtained by fitting quantum efficiency curves. Results show that sample 1 has a better spectral response than sample 2 at the range of short-wavelength. This work provides a reference for the structure design of the AlGaN photocathode. -
References
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