Variations of Channel Conductance in AlGaN/GaN Structure with Sub-Bandgap Laser Light and Above-Bandgap Illuminations

Chang, Yang-Chyuan; Li, Yun Li; Lin, Tzung Han; Sheu, Jinn-Kong

doi:10.1143/jjap.46.3382

Cited by 6 publications

(3 citation statements)

References 10 publications

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“…The decay of the conductance can be fitted with a single exponential function with a time constant of ≈ 400 s. This extra‐long decay in conductance after the termination of light illumination is similar to the persistent photoconductivity observed in AlGaN/GaN heterostructures, which is typically explained by carrier de‐trapping from the surface states. [ 12 ] By comparison, no conductance variation is observed if no elliptical nanodisks are presented within the area between the electrodes, shown as the red curve in Figure 1d. These results indicate that the generation of surface plasmon induces an increase of channel conductance.…”

Section: Resultsmentioning

confidence: 99%

Quantifying the Plasmonic Generation Rate of Non‐Thermal Hot Carriers with an AlGaN/GaN High‐Electron‐Mobility Transistor

Liu

Lai

et al. 2021

Advanced Science

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Plasmonic generation of hot carriers in metallic nanostructures has attracted much attention due to its great potential in several applications. However, it is highly debated whether the enhancement is due to the hot carriers or the thermal effect. Here, the ability to exclude the thermal effect and detect the generation of non-thermal hot carriers by surface plasmon is demonstrated using an AlGaN/GaN high-electron-mobility transistor. This ultrasensitive platform, which demonstrates at least two orders of magnitude more sensitivity compared to the previous reports, can detect the hot carriers generated from discrete nanostructures illuminated by a continuous wave light. The quantitative measurements of hot carrier generation also open a new way to optimize the plasmonic nanoantenna design in many applications.

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Section: Resultsmentioning

confidence: 99%

Quantifying the Plasmonic Generation Rate of Non‐Thermal Hot Carriers with an AlGaN/GaN High‐Electron‐Mobility Transistor

Liu

Lai

et al. 2021

Advanced Science

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“…In 2006, Okada et al [15] reported that the blue LED and incandescent lamp can lead to a large threshold voltage shift in AlGaN/GaN HFETs, but the red LED illumination almost cannot change the threshold voltage. In 2007 and 2010, Chang et al [16,17] reported that the channel resistance increases when the device is illuminated with subbandgap energy photons after the UV-induced variation becomes stable. The reason is the positively charged surface states captured of excess electrons.…”

Section: Introductionmentioning

confidence: 99%

Abnormal phenomenon of source-drain current of AlGaN/GaN heterostructure device under UV/visible light irradiation*

Liu¹,

Shen²,

Xing³

et al. 2021

Chinese Phys. B

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We report an abnormal phenomenon that the source-drain current (I D) of AlGaN/GaN heterostructure devices decreases under visible light irradiation. When the incident light wavelength is 390 nm, the photon energy is less than the band gaps of GaN and AlGaN whereas it can causes an increase of I D. Based on the UV light irradiation, a decrease of I D can still be observed when turning on the visible light. We speculate that this abnormal phenomenon is related to the surface barrier height, the unionized donor-like surface states below the surface Fermi level and the ionized donor-like surface states above the surface Fermi level. For visible light, its photon energy is less than the surface barrier height of the AlGaN layer. The electrons bound in the donor-like surface states below the Fermi level are excited and trapped by the ionized donor-like surface states between the Fermi level and the conduction band of AlGaN. The electrons trapped in ionized donor-like surface states show a long relaxation time, and the newly ionized donor-like surface states below the surface Fermi level are filled with electrons from the two-dimensional electron gas (2DEG) channel at AlGaN/GaN interface, which causes the decrease of I D. For the UV light, when its photon energy is larger than the surface barrier height of the AlGaN layer, electrons in the donor-like surface states below the Fermi level are excited to the conduction band and then drift into the 2DEG channel quickly, which cause the increase of I D.

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“…The paper presents spectral measurements of the sheet resistance of AlGaN/GaN HEMT‐type heterostructures grown on sapphire substrate. Previously, the impact of light on AlGaN/GaN heterostructure was investigated, but a spectral examination that also involves the defining of absorption edge and observation of deep energetic levels occurrence has not yet been conducted.…”

Section: Introductionmentioning

confidence: 99%

Light Influence on the Sheet Resistance of AlGaN/GaN Heterostructures Grown by MOVPE Technique

Pokryszka

Szymański

Paszkiewicz

2018

Crystal Research and Technology

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Sheet resistance is the most commonly used electrical parameters of thin films; the special feature of sheet resistance is its scalability that is often used in the qualitative assessment of its usefulness. That is why it is so often used as an electrical parameter in the evaluation of created layers by various epitaxial methods. In materials based on AIIIN compounds, there is a built-in electric field that disturbs the electrical charge inside the heterostructure. The perturbed distribution of electrical charge inside the heterostructure creates donor states on the surface that increase the surface resistance value. The paper presents the influence of UV radiation on surface states affecting the sheet resistance of AlGaN/GaN heterostructures. Based on the presented method, influence of light on sheet resistance is examined and spectral characteristics of AlGaN/GaN heterostructure are obtained. Measurements are performed using the Hall Bar test structure fabricated in AlGaN/GaN heterostructure grown by metal organic vapor phase epitaxy methods. The Hall bar test structures are investigated at room temperature under the light excitation in the range from 280 to 640 nm.

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Variations of Channel Conductance in AlGaN/GaN Structure with Sub-Bandgap Laser Light and Above-Bandgap Illuminations

Cited by 6 publications

References 10 publications

Quantifying the Plasmonic Generation Rate of Non‐Thermal Hot Carriers with an AlGaN/GaN High‐Electron‐Mobility Transistor

Quantifying the Plasmonic Generation Rate of Non‐Thermal Hot Carriers with an AlGaN/GaN High‐Electron‐Mobility Transistor

Abnormal phenomenon of source-drain current of AlGaN/GaN heterostructure device under UV/visible light irradiation*

Light Influence on the Sheet Resistance of AlGaN/GaN Heterostructures Grown by MOVPE Technique

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