Photonics Research, Volume. 10, Issue 1, 111(2022)

Ultrahigh detectivity, high-speed and low-dark current AlGaN solar-blind heterojunction field-effect phototransistors realized using dual-float-photogating effect

Kai Wang1、†, Xinjia Qiu1、†, Zesheng Lv1, Zhiyuan Song1, and Hao Jiang1,2,3、*
Author Affiliations
  • 1School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
  • 2State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China
  • 3Guangdong Engineering Technology R & D Center of Compound Semiconductors and Devices, Sun Yat-sen University, Guangzhou 510275, China
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    Figures & Tables(7)
    (a) Schematic illustration of the PG-HFEPT and (b) its cross-sectional view. (c) Schematic diagram and optical image of the interdigitated electrodes, mentioning the device dimensions.
    (a) Transmission and reflection spectra of the epitaxial structure with p-type photogate. (b) XRD RSM for the epitaxial structure taken around (105) reflection, in which the dashed lines correspond to fully strained (R%=0%) and fully relaxed (R%=100%) states of the Al0.4GaN channel layer. Simulated energy band diagram for the devices (c) without and (d) with the p-type AlGaN photogate.
    Dark and illuminated I-V characteristics of the HFEPTs (a) with and (b) without the p+-Al0.4GaN top photogate. The inset of (b) is the linear plot of the I-V curve. (c) I-V characteristics of the Ti/Al/Ni/Au Ohmic electrodes for the two HFEPTs. (d) Spectral responsivity of the PG-HFEPT under 1 V and 3 V bias. The inset is the corresponding spectral photocurrent.
    (a) Schematic diagram of the photogenerated carriers and their movement in the absorber, barrier, and channel layers of PG-HFEPT. Schematic band diagrams of (b) the top p-type photogate heterojunction and (c) the virtual back-photogate heterojunction together with the barrier layer outside the p-photogate under dark and illumination conditions.
    (a) Iph-V curves of the PG-HFEPT measured at different incident power densities of a 260 nm LED. (b) Dependence of Iph on incident power density. (c) Responsivity versus voltage characteristics under different incident power densities. (d) Dependence of responsivity on incident power density.
    (a) Noise power density spectra of the PG-HFEPT and HFEPT measured at different biases. (b) Impulse response of the two phototransistors measured at 3 V bias. The inset is the time-dependent photoresponse of the two phototransistors at 3 V bias measured at 260 nm irradiation with a 30 s on/off cycle.
    • Table 1. Comparison of Characteristic Parameters of Our Detectors Using Dual-Photogating Effects to Those of Published Solar-Blind UV Photodetectors

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      Table 1. Comparison of Characteristic Parameters of Our Detectors Using Dual-Photogating Effects to Those of Published Solar-Blind UV Photodetectors

      MaterialTypeD* (cmHz1/2W1)R (A/W)Iph/Idark ratioτr/τf (ms)Refs.
      AlGaNHFEPT2.84×10151.9×104 (5 V)1.0×1080.0044/0.591This work
      2.91×1017a
      Cu2O/β-Ga2O3Heterojunction5.20×1011b0.053 (16  V)200/200[26]
      Cs3Cu2I5/β-Ga2O3Heterojunction2.40×1080.0023 (0 V)5.1×10437/45[27]
      β-Ga2O3MSM9.8×1015b46 (20 V)1.0×1080.0009/0.0119[28]
      AlGaNMSM1.76×1012b3.63 (5 V)1130/133[29]
      AlGaNp-i-n4.20×1014c0.131 (5 V)4.8×105140/8200[32]
      AlGaN/GaNSchottky2.60×1012c0.09 (50 V)[33]
      AlGaNp-i-n2.00×1014c0.09 (5 V)[34]
      AlGaNAPD1.40×1014c0.13 (20 V)1.0×103[35]
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    Kai Wang, Xinjia Qiu, Zesheng Lv, Zhiyuan Song, Hao Jiang. Ultrahigh detectivity, high-speed and low-dark current AlGaN solar-blind heterojunction field-effect phototransistors realized using dual-float-photogating effect[J]. Photonics Research, 2022, 10(1): 111

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    Paper Information

    Category: Optical Devices

    Received: Sep. 28, 2021

    Accepted: Nov. 4, 2021

    Published Online: Dec. 13, 2021

    The Author Email: Hao Jiang (stsjiang@mail.sysu.edu.cn)

    DOI:10.1364/PRJ.444444

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