AlGaN Ultraviolet Metal–Semiconductor–Metal Photodetectors with Reduced Graphene Oxide Contacts

Pandit, Bhishma; Cho, Jaehee

doi:10.3390/app8112098

Cited by 16 publications

(14 citation statements)

References 29 publications

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“…AlGaN 22,23 . In this regard, the combination of graphene electrodes and AlGaN/GaN heterostructures may yield an excellent UV photodetector, considering the high transparency of graphene in the UV spectral region and the high electrical conductivities of graphene and 2DEG, which would benefit efficient charge collection in the photodetector.…”

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confidence: 99%

Dual-functional ultraviolet photodetector with graphene electrodes on AlGaN/GaN heterostructure

Pandit

Schubert

Cho

2020

Sci Rep

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A dual-functional ultraviolet (UV) photodetector with a large UV-to-visible rejection ratio is presented, in which interdigitated finger-type two-dimensional graphene electrodes are introduced to an AlGaN/GaN heterostructure. Two photocurrent generation mechanisms of photovoltaic and photoconductive dominances coexist in the device. The dominance of the mechanisms changes with the induced bias voltage. Below a threshold voltage, the device showed fairly low responsivities but fast response times, as well as a constant photocurrent against the induced bias. However, the opposite characteristics appeared with high bias voltage. Specifically, above the threshold voltage, the device showed high responsivities with additional gain, but slow rise and recovery times. For instance, the responsivity of 10.9 A/W was observed with the gain of 760 at the induced bias voltage of 5 V. This unique multifunctionality enabled by the combination of an AlGaN/GaN heterostructure with graphene electrodes facilitates the development of a single device that can achieve multiple purposes of photodetection.

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confidence: 99%

Dual-functional ultraviolet photodetector with graphene electrodes on AlGaN/GaN heterostructure

Pandit

Schubert

Cho

2020

Sci Rep

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“…As shown in Figure S7 (Supporting Information), the α of InGaN photodetector and InN/InGaN heterojunction photodetector is 0.038 and 0.042, respectively, which suggests a complex process of photogenerated carriers excitation, recombination, trapping, and diffusion. [40] Moreover, the spectral responsivity (R) of the photodetector was evaluated by the following formula: [41] R I I PS…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, the spectral responsivity ( R ) of the photodetector was evaluated by the following formula: [ 41 ]

\begin{array}{*{20}{c}}{R\; = \frac{{{I_{{\rm{light}}}}\; - \;{I_{{\rm{dark}}}}}}{{PS}}\;}\end{array}

where I light and I dark are the photocurrents and the dark current, respectively; P is the light power density (as shown in Figure S6b, Supporting Information), and S is the irradiated area of a photodetector device (0.1256 mm 2 ). As shown in Figure 3c, the maximum value of R for the InN/InGaN NRA heterojunction photodetector is 9.27 A W −1 at 377 nm, and the maximum value of R for the InGaN photodetector is 0.38 A W −1 (Figure S6c, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Axial InN/InGaN Nanorod Array Heterojunction Photodetector with Ultrafast Speed

Chai

Liu

Chen

et al. 2023

Adv Elect Materials

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requires the photodetection wavelength of the photo detector could match the source wavelength. [4][5][6] In this regard, the bandgap tunable semiconductor and its fabricated photodetector with fast response speed have become a research hotspot. [7][8][9] InGaN semiconductors can achieve wavelength-selective absorption owning to their tunable bandgap (0.65-3.4 eV), which is adjusted by varying the composition of Indium (In). [10][11][12] Thanks to the development of semiconductor industry technology, the InGaN photodetector with PIN and integrated structure has been used in visible light communication systems. [13][14][15] However, the above InGaN-based ultrafast photodetector heavily relies on expensive, slow, complex material growth and chip preparation processes. [16] Accordingly, the development of a simple-structured photodetector with a fast response speed is urgently needed. [17] The photodetector with simple heterojunction demonstrates fast photodetection owing to the built-in electric field to facilitate carrier separation and transport. [18,19] Among the III-nitrides materials, on account of the high electron mobility (4400 cm 2 V −1 s −1 ), the InN semiconductors are widely used to fabricate fast photodetectors. [20,21] Regarding the mentioned above, the InN/InGaN heterojunction is considered a promising candidate for preparing a fast photodetector. This is well known that the high-performance photodetector composed of wide band gap materials lies on top of the narrow band gap materials, thus the InGaN should be grown on the top of InN. [22] However, this InN/InGaN heterojunction cannot be realized due to the growth temperature of InGaN is higher than the dissociation temperature of InN.The dilemma above might be solved by introducing 1D InN nanorod array (NRA) to InGaN films, which could not only relax the strain to form defect-free lattice-mismatched heterostructures but also break through the material arrangement limit of the bandgap. [23,24] Previous research has reported an InN/InGaN heterojunction with the structure of InN NRA on the InGaN epilayer and applied it to optoelectronic devices. [25,26] Nevertheless, this method needs phase-separated from In-rich InGaN buffer as the nucleation sites, which will cause the diameter uniformity of these structures to be poor. The axial heterojunction structure is an effective strategy, on one hand, the diameter uniformity of InN could be controlled, on the other hand, the 1D geometry could confine carriers separation in a very small NRA Due to wavelength-selective characteristics, the InGaN-based photodetectors show bright prospects in visible light communication and fast imaging system. However, the application of InGaN photodetectors with simple structures is limited in the above field owing to the slow response speed. Herein, an ultrafast photodetector based on axial InN/InGaN nanorod array (NRA) heterojunction is prepared through a self-catalytic high (930 °C) and low (400 °C) temperature two-step growth method by molecular beam epitaxy (MBE). The perf...

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“…It reflects the sensitivity of incident light energy on the surface of the device. R was presented as a function of EQE that could be denoted as [ 11 ]

R = \frac{J_{\text{ph}}}{P_{\text{in}}} = \text{EQE} \frac{\lambda q}{h c}

where λ is the wavelength of the incident light, q is the elementary charge, and c is the velocity of light in a vacuum. D * of PDs is related to R , and I dark is the dark current, A is the active area, D * can be calculated by the formula [ 12 ]

$$D^{*} = \frac{A^{\frac{1}{2}} R}{\left(\left(\right.

…”

Section: Resultsmentioning

confidence: 99%

AlGaN‐Based Solar‐Blind Ultraviolet Detector with a Response Wavelength of 217 nm

Zhang,

Zheng,

Cheng

et al. 2023

Physica Status Solidi (a)

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The research of the high Al(x = 0.75) component has always been the focus of the AlGaN solar‐blind ultraviolet (UV) detector. However, due to the lattice and thermal mismatch between the AlGaN and the underlying substrate under existing mainstream heteroepitaxial growth methods, the large density of defects, e.g., point defects, screw dislocations, and edge dislocations, has hindered the performances of AlGaN‐based solar‐blind UV photodetectors. A short superlattice polarization‐induced P‐type doping growth technique is used to fabricate a high‐performance AlGaN‐based back‐illuminated solar‐blind UV p‐i‐n photodetector (PD) fabricated on sapphire substrates. The back‐illuminated AlGaN UV‐PD shows a high external quantum efficiency of 70.2%. The peak responsivity (R) reaches 123 mA W−1 at −5 V with a wavelength of 217 nm. Meanwhile, the dark current density is 2.21 × 10−8 A cm−2. Additionally, the UV/visible rejection ratio for the detectors exceeds four orders of magnitude, and the detectivity (D*) is calculated to be 6.7 × 1012 cm Hz1/2 W−1. The device performance parameters can be attributed to the quality of the epilayer and heterojunctions. This technology provides new ideas for nitride semiconductor materials, further bringing a breakthrough in a wide‐bandgap electronics device.

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AlGaN Ultraviolet Metal–Semiconductor–Metal Photodetectors with Reduced Graphene Oxide Contacts

Cited by 16 publications

References 29 publications

Dual-functional ultraviolet photodetector with graphene electrodes on AlGaN/GaN heterostructure

Dual-functional ultraviolet photodetector with graphene electrodes on AlGaN/GaN heterostructure

Axial InN/InGaN Nanorod Array Heterojunction Photodetector with Ultrafast Speed

AlGaN‐Based Solar‐Blind Ultraviolet Detector with a Response Wavelength of 217 nm

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