Infrared photodetectors (IRPDs) play a critical role in various fields such as optical communication, thermal imaging, and environmental monitoring. To effectively suppress dark current and enhance optoelectronic performance, this work proposes an infrared photodetector based on a recessed-gate field-effect transistor (FET) architecture incorporating a graded energy-band barrier layer. Benefiting from the barrier effect at the heterojunction interface and efficient carrier separation, the device exhibits a low dark current of 4.2<InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\times \)</EquationSource> </InlineEquation>10<InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(^{-8}\)</EquationSource> </InlineEquation>A under a bias voltage of <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\({V_{ds}}\)</EquationSource> </InlineEquation>=4V, and generates a photocurrent exceeding 3.2<InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\times \)</EquationSource> </InlineEquation>10<InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(^{-7}\)</EquationSource> </InlineEquation>A under 1550nm illumination. The detector demonstrates a maximum responsivity (R) of 1.07A/W and an external quantum efficiency (EQE) of 92.2%, with broadband spectral responsivity spanning 0.8-1.8<InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\upmu \)</EquationSource> </InlineEquation>m, and a room-temperature specific detectivity (<InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(D^*\)</EquationSource> </InlineEquation>) of 2.06<InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(\times \)</EquationSource> </InlineEquation>10<InlineEquation ID="IEq9"> <EquationSource Format="TEX">\(^{9}\)</EquationSource> </InlineEquation>Jones. Moreover, the response time is shortened to 0.89<InlineEquation ID="IEq10"> <EquationSource Format="TEX">\(\textrm{ns}\)</EquationSource> </InlineEquation>. By introducing an anti-reflection (AR) coating to enhance optical coupling, the responsivity and quantum efficiency are further improved by 36.54% and 20%, respectively. Overall, the InGaAs recessed-gate FET with a graded barrier layer exhibits outstanding infrared detection performance and holds significant potential for high-speed and broadband infrared sensing applications.

Design and performance study of a recessed-gate FET infrared photodetector featuring a compositionally graded InAlAs barrier layer

期刊论文
发表日期：

2026年2月17日

查看全文

Jiang Wang,
Jiabin Li,
Yinghang Lei,
Lin Zhou

摘要

Infrared photodetectors (IRPDs) play a critical role in various fields such as optical communication, thermal imaging, and environmental monitoring. To effectively suppress dark current and enhance optoelectronic performance, this work proposes an infrared photodetector based on a recessed-gate field-effect transistor (FET) architecture incorporating a graded energy-band barrier layer. Benefiting from the barrier effect at the heterojunction interface and efficient carrier separation, the device exhibits a low dark current of 4.2 \(\times \) 10 \(^{-8}\) A under a bias voltage of \({V_{ds}}\) =4V, and generates a photocurrent exceeding 3.2 \(\times \) 10 \(^{-7}\) A under 1550nm illumination. The detector demonstrates a maximum responsivity (R) of 1.07A/W and an external quantum efficiency (EQE) of 92.2%, with broadband spectral responsivity spanning 0.8-1.8 \(\upmu \) m, and a room-temperature specific detectivity ( \(D^*\) ) of 2.06 \(\times \) 10 \(^{9}\) Jones. Moreover, the response time is shortened to 0.89 \(\textrm{ns}\) . By introducing an anti-reflection (AR) coating to enhance optical coupling, the responsivity and quantum efficiency are further improved by 36.54% and 20%, respectively. Overall, the InGaAs recessed-gate FET with a graded barrier layer exhibits outstanding infrared detection performance and holds significant potential for high-speed and broadband infrared sensing applications.