Light-triggered 2D electron gas in a GaN-based HEMT with sandwiched p-GaN layers

Wang, Yu; Hao, Quan; Liu, Hangzan; Han, Lixiang; Gao, Wei; Wang, Xiaozhou; Li, Jingbo

doi:10.1364/ol.499084

Cited by 3 publications

(5 citation statements)

References 26 publications

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“…R is calculated by the formula of R = I photo − I dark A , I photo and I dark represent the photocurrent and dark current under the same bias condition, and A represent the area of gate region. The responsivity linearly increases as the light intensity decreases in double logarithmic coordinates, following a relationship of the form R ∝ P β–1 , where β is 0.35 and mainly related to the process including generation, recombination and trapping of the carriers. ,− For the as-fabricated AlGaN/GaN double-channel HEMT PD, the highest responsivity at 9.7 μW/cm 2 was remarkable as 2.1 × 10 7 A/W, which was much higher than that of previously reported GaN HEMT PDs, as shown in Table . This behavior was further evaluated by the term external quantum efficiency (EQE), which can be calculate by EQE = h c R λ q , where h , c , q , and λ are Planck’s constant, velocity of light, elementary electric charge, and light wavelength, respectively .…”

Section: Resultsmentioning

confidence: 83%

Ultrahigh-Responsivity Ultraviolet Photodetectors Based on AlGaN/GaN Double-Channel High-Electron-Mobility Transistors

Wang,

Feng,

Zhong

et al. 2023

ACS Photonics

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In this work, high-performance ultraviolet (UV) photodetectors (PDs) based on an AlGaN/GaN double-channel high-electron-mobility transistor (HEMT) were fabricated and investigated using 360 nm illumination. The design of the novel device structure introduces double two-dimensional electron gas channels, which remarkably improve the effectiveness in the collection of photogenerated carriers and make it work as a twoterminal normally off device. The device exhibited a high responsivity of 2.1 × 10 7 A/W and a high specific detectivity of 1.7 × 10 15 Jones under the illumination of 9.7 μW/cm 2 , indicating the excellent capability of detecting an ultraweak signal. Meanwhile, a distinguished transient performance was also observed when it operated under 500 Hz pulse illumination. Combining fabrication conciseness and outstanding performance advantages, the proposed AlGaN/GaN double-channel HEMT UV PD shows promising potential in the development of next-generation UV PDs.

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Section: Resultsmentioning

confidence: 83%

Ultrahigh-Responsivity Ultraviolet Photodetectors Based on AlGaN/GaN Double-Channel High-Electron-Mobility Transistors

Wang,

Feng,

Zhong

et al. 2023

ACS Photonics

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“…Moreover, a significant number of electrons accumulated within the quantum wells, increasing the light-induced electron concentration. As a result, our designed GaN HEMT PD enables high R and excellent photosensitivity under UV illumination …”

Section: Resultsmentioning

confidence: 95%

“…As a result, our designed GaN HEMT PD enables high R and excellent photosensitivity under UV illumination. 30 Most importantly, according to the I ds −V ds curves, PDCR is a function of P at V ds = 5 V, and various light power intensities under 365 nm illumination are described in Figure 6a. PDCR monotonously increases from 1.3 × 10 7 to 7 × 10 8 at V ds = 5 V when P is ranging from 0.235 to 286.39 mW/cm 2 .…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Furthermore, the response speed, including rise time (τ r ) and decay time (τ d ), is plotted in Figure d. The rising and falling edges are respectively fitted by using the following equations: I false( t false) = I dark + A exp false( t / τ normalr false) I false( t false) = I dark + A exp false( t / τ normald false) where t , A , and τ, respectively, refer to the duration of the on/off state, the scaling constant, and the time constant. As a result, τ r /τ d can be extracted as 1.55 and 1.60 ms, respectively, indicating that the HEMT UV PD possessed a fast response speed.…”

Section: Resultsmentioning

confidence: 99%

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A Low-Dark-Current and High-Responsivity Ultraviolet Photodetector Based on a Recessed-Gate AlGaN/GaN Enhanced-Type High-Electron-Mobility Transistor

Wang,

Cai,

et al. 2024

ACS Appl. Electron. Mater.

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In recent years, an ultraviolet (UV) photodetector (PD) utilizing two-dimensional electron gas (2DEG) formed at the AlGaN/GaN heterostructure as a GaN-based recessed-gate high-electron-mobility transistor (HEMT) has become a hot topic for UV and solar blind detection. Herein, a GaN-based HEMT UV PD with a recessed gate was prepared, and the conductive channel is closed due to the GaN-based recessed gate, which keeps the device normally off without a p-GaN gate or extra gate bias; the 2DEG is fully depleted with an extremely low dark current density of 1.87 × 10 −6 mA/mm under dark conditions. Under 365 nm UV irradiation, the conductive region is restored and the device exhibits a high photo-to-dark current ratio (PDCR) of 7 × 10 8 , a peak responsivity of 1.75 × 10 4 A/W, a high specific detectivity (D*) of 4.87 × 10 16 Jones, and a superior UV-tovisible rejection ratio of 2.9 × 10 6 . Moreover, a fast response time of 1.55/1.60 ms can be maintained, which is ascribed to the use of triethylgallium in intrinsic GaN (i-GaN) epitaxy to achieve improved crystalline quality, the incorporation of a doped AlGaN layer to reduce the scattering of 2DEGs by positive polarity impurities, and the implementation of asymmetric electrodes for rapid separation and transfer of photogenerated electron−hole pairs. The results indicate that our designed recessed-gate AlGaN/GaN HEMT is an ideal UV PD with high responsivity, low dark current, and rapid response time.

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“…17 However, the latter structure displays a slower response time than that of the p-GaN gate. In addition, GaN photodetectors with other structures, such as MOSFET-type, 18 GaN HEMT-type with sandwiched p-GaN layers, 19 and double channels, 20 have also achieved good photodetection performance. In this study, we demonstrate UVPD arrays based on recessed-gated HEMTs with a p-GaN buried layer under a 2DEG channel.…”

Section: ■ Introductionmentioning

confidence: 99%

High-Performance Ultraviolet Photodetector Arrays Based on Recessed-Gate HEMT with a Buried p-GaN Layer

Liu,

Wang,

Liu

et al. 2024

ACS Appl. Electron. Mater.

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GaN, due to its large band gap and high carrier mobility, has been widely used in fast-response ultraviolet (UV) photodetectors (PDs). The existing junction-based and twodimensional electron gas (2DEG)-based devices have different focuses on the performance of ultraviolet detection. To achieve comprehensive performance, we fabricate a high-performance UVPD utilizing a GaN recessed-gate high electron mobility transistor (HEMT) integrated with a p-GaN buried layer. Benefiting from the effective p-GaN/u-GaN depletion junction, the device has a low dark current of 1.75 × 10 −9 A at a voltage bias (V ds ) of 2 V. Under 365 nm illumination, the recovery of 2DEG is obtained and results in an ultrahigh photocurrent exceeding 1 mA at V ds = 2 V. As a result, a maximum responsivity (R) of 532 A/W, an external quantum efficiency of 1.81 × 10 5 %, and a specific detectivity (D*) of 1.09 × 10 14 Jones are attained at a light power density (P) of 0.24 mW cm −2 . Moreover, the influence of oxygen plasma treatment on the gate recess is explored. The response time is shortened from 1.07/1.20 to 0.79/1.05 ms, and the maximum I light /I dark ratio is increased by more than 10 times. Such high performance substantiates that the structure of GaN recessed-gate HEMT with p-GaN buried layer architecture holds great promise for the creation of an outstanding UV photodetector.

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Light-triggered 2D electron gas in a GaN-based HEMT with sandwiched p-GaN layers

Cited by 3 publications

References 26 publications

Ultrahigh-Responsivity Ultraviolet Photodetectors Based on AlGaN/GaN Double-Channel High-Electron-Mobility Transistors

Ultrahigh-Responsivity Ultraviolet Photodetectors Based on AlGaN/GaN Double-Channel High-Electron-Mobility Transistors

A Low-Dark-Current and High-Responsivity Ultraviolet Photodetector Based on a Recessed-Gate AlGaN/GaN Enhanced-Type High-Electron-Mobility Transistor

High-Performance Ultraviolet Photodetector Arrays Based on Recessed-Gate HEMT with a Buried p-GaN Layer

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