Quantitative analysis of carrier concentration and electric field in non-uniform quantum well infrared photodetectors
6 affiliations
- 1School of Microelectronics, Shanghai University Shanghai 201899 China
- 2State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences Shanghai 200083 China
- 3University of Chinese Academy of Sciences Beijing 100049 China
- 4School of Physical Science and Technology, ShanghaiTech University Shanghai 201210 China
- 5Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Bejing National Laboratory for Condensed Matter Physics, Institute of Physics, ChineseAcademy of Sciences Beijing 100190 China
- 6Center of Materials and Optoelectronics Engineering, University of Chinese Academy of Sciences Beijing 100049 China
Abstract
Semiconductor non-uniform quantum wells (NUQWs) improve long-wavelength infrared detection by resolving the trade-off between dark current and responsivity found in conventional uniform structures. By grading doping and barrier thicknesses, these designs enhance absorption in highly doped areas while strengthening electric fields in low-doped regions to trigger carrier multiplication. However, the actual carrier concentration profile within quantum wells (QWs) has long lacked effective experimental verification. In this work, we employed calibrated scanning spreading resistance microscopy (SSRM) to realize nanoscale quantitative analysis of the carrier distribution within GaAs/AlGaAs quantum well infrared photodetector (QWIP) structures. The non-uniform design successfully led to reduction of dark current by nearly 4 times compared to that of the uniform counterparts, thus elevating the background limited infrared photodetection (BLIP) temperature by 4 K. On the other hand, the responsivity failed to show the expected enhancement. Simulations revealed that the deviation of electron densities in the low-doped QWs induces a weak local electric field of approximately 1.7 kV cm−1, which is significantly below the threshold field to trigger impact ionization. These findings guide the design of an optimized asymmetric gradient-doping structure capable of generating a strong electric field of up to 13.8 kV cm−1 in the collection region, thereby achieving high gain while maintaining low dark current.
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BibTeX
@article{chen2026quantitative,
title = {{Quantitative analysis of carrier concentration and electric field in non-uniform quantum well infrared photodetectors}},
author = {Zhen Chen and Rui Xin and Li Yu and Zhen Deng and Shenjun Wang and Yue Cheng and Hui Xia and Shufan Yao and Tianxin Li},
journal = {Nanoscale Advances},
year = {2026},
month = sep,
doi = {10.1039/d6na00204h},
url = {https://doi.org/10.1039/d6na00204h},
note = {CC BY-NC 3.0},
}
RIS
TY - JOUR
TI - Quantitative analysis of carrier concentration and electric field in non-uniform quantum well infrared photodetectors
AU - Zhen Chen
AU - Rui Xin
AU - Li Yu
AU - Zhen Deng
AU - Shenjun Wang
AU - Yue Cheng
AU - Hui Xia
AU - Shufan Yao
AU - Tianxin Li
PY - 2026
DA - 2026/09/23
JO - Nanoscale Advances
DO - 10.1039/d6na00204h
UR - https://doi.org/10.1039/d6na00204h
AB - Semiconductor non-uniform quantum wells (NUQWs) improve long-wavelength infrared detection by resolving the trade-off between dark current and responsivity found in conventional uniform structures. By grading doping and barrier thicknesses, these designs enhance absorption in highly doped areas while strengthening electric fields in low-doped regions to trigger carrier multiplication. However, the actual carrier concentration profile within quantum wells (QWs) has long lacked effective experimental verification. In this work, we employed calibrated scanning spreading resistance microscopy (SSRM) to realize nanoscale quantitative analysis of the carrier distribution within GaAs/AlGaAs quantum well infrared photodetector (QWIP) structures. The non-uniform design successfully led to reduction of dark current by nearly 4 times compared to that of the uniform counterparts, thus elevating the background limited infrared photodetection (BLIP) temperature by 4 K. On the other hand, the responsivity failed to show the expected enhancement. Simulations revealed that the deviation of electron densities in the low-doped QWs induces a weak local electric field of approximately 1.7 kV cm−1, which is significantly below the threshold field to trigger impact ionization. These findings guide the design of an optimized asymmetric gradient-doping structure capable of generating a strong electric field of up to 13.8 kV cm−1 in the collection region, thereby achieving high gain while maintaining low dark current.
SN - 2516-0230
ER -