Reduction of Persistent Photoconduction with IGZO/ZnON-Tandem-Structure Visible–Near-Infrared Phototransistors

Lee, Hyun Mo; Kim, Yoon Seo; Rim, You Seung; Park, Jin‐Seong

doi:10.1021/acsami.1c02593

Cited by 7 publications

(9 citation statements)

References 27 publications

(43 reference statements)

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“…Since ZnON has an indirect energy bandgap, n = 2 in Equation ( 2). [36,37] Moreover, ZnON exhibited a bandgap of 1.66 eV, which is slightly wider than previously reported values, [38,39] which resulted from the annealing process changing the oxygen and nitrogen concentrations in the ZnON layer (Figure S5b,c and Note S4, Supporting Information). The bandgaps of InAs-ME and InAs-InCl 3 were calculated from the first exciton energy in the UV-vis spectra (Figure S2a, Supporting Information), and the total energy band diagrams are shown in Figure 2g.…”

Section: Resultsmentioning

confidence: 67%

Ultrasensitive Near‐Infrared InAs Colloidal Quantum Dot‐ZnON Hybrid Phototransistor Based on a Gradated Band Structure

et al. 2023

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Amorphous metal oxide semiconductor phototransistors (MOTPs) integrated with colloidal quantum dots (QDs) (QD-MOTPs) are promising infrared photodetectors owing to their high photoconductive gain, low off-current level, and high compatibility with pixel circuits. However, to date, the poor mobility of conventional MOTPs, such as indium gallium zinc oxide (IGZO), and the toxicity of lead (Pb)-based QDs, such as lead sulfide and lead selenide, has limited the commercial applications of QD-MOTPs. Herein, an ultrasensitive QD-MOTP fabricated by integrating a high-mobility zinc oxynitride (ZnON)-based MOTP and lead-free indium arsenide (InAs) QDs is demonstrated. A new gradated bandgap structure is introduced in the InAs QD layer that absorbs infrared light, which prevents carriers from moving backward and effectively reduces electron-hole recombination. Chemical, optical, and structural analyses confirm the movement of the photoexcited carriers in the graded band structure. The novel QD-MOTP exhibits an outstanding performance with a responsivity of 1.15 × 10 5 A W −1 and detectivity of 5.32 × 10 16 Jones at a light power density of 2 μW cm −2 under illumination at 905 nm.

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Section: Resultsmentioning

confidence: 67%

Ultrasensitive Near‐Infrared InAs Colloidal Quantum Dot‐ZnON Hybrid Phototransistor Based on a Gradated Band Structure

et al. 2023

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“…Since the E CBM of ZnON is lower than that of IGZO, the probability for recombination between accumulated electrons in the CBM of ZnON and ionized V O states of IGZO becomes higher. 54 We found that the E CBM of ZnON 5 was lower than that of ZnON 4, which would enhance the recombination capability of ZnON 5 with the ionized V O states of IGZO. At the same time, the accumulated electrons are more likely to recombine with a higher VBM of ZnON 5 in Hetero 2 TFT than ZnON 4 in Hetero 1 TFT.…”

Section: ■ Resultsmentioning

confidence: 72%

“…All recombination mechanisms (1–3) contributed to a much faster decay of the drain current in Hetero 1 and Hetero 2 TFT, which was not possible in IGZO TFT. Since the E CBM of ZnON is lower than that of IGZO, the probability for recombination between accumulated electrons in the CBM of ZnON and ionized V O states of IGZO becomes higher . We found that the E CBM of ZnON 5 was lower than that of ZnON 4, which would enhance the recombination capability of ZnON 5 with the ionized V O states of IGZO.…”

Section: Resultsmentioning

confidence: 75%

“…We present the energy band diagram to explain the photodynamic behavior of Hetero 1 and Hetero 2 TFT. Figure e shows the energy band diagram of IGZO/ZnON heterojunction TFTs under the light-on state at a V GS of −10 V, assuming the electron affinity of IGZO as ∼4.2 eV. , When the visible lasers were illuminated on the IGZO/ZnON heterojunction, the incident photons would induce I ph from each of the materials. The photoionization from the V O states of IGZO and the V N states of ZnON and the band-to-band generation of ZnON are responsible.…”

Section: Resultsmentioning

confidence: 99%

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In Situ IGZO/ZnON Phototransistor Free of Persistent Photoconductivity with Enlarged Spectral Responses

Jang

Lee

2022

ACS Appl. Electron. Mater.

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We present comprehensive studies on ZnON thin films deposited by radio-frequency (RF) magnetron sputtering using a ZnO target under various nitrogen plasma conditions. A ZnON thin film grown under the highest nitrogen partial flow rate exhibits the lowest optical bandgap of 1.84 eV, excellent stability upon air exposure, an amorphous/nanocrystalline structure, and the strongest stoichiometric Zn3N2 chemical states. The highest field-effect mobility of 4.28 cm2 V–1 s–1, the largest responsivity, and the negligible persistent photoconductivity (PPC) effect against visible light are also realized by the thin-film transistor (TFT) configuration. The device performance of the ZnON phototransistor is compared to those of other oxide semiconductors of ZnO and InGaZnO (IGZO). Finally, an IGZO/ZnON phototransistor, where ZnON was deposited on top of IGZO by an in situ process, demonstrates high specific detectivities (1.65 × 1013, 1.35 × 1013, and 2.0 × 1014 Jones against red, green, and blue photons, respectively) without the PPC effect. We examined the photoluminescence (PL) spectra of ZnON with respect to nitrogen-associated defects, which are yet to be discussed, and emphasize that our optimum deposition process is free of the poisoning effect. To our knowledge, this is the first report on a ZnON phototransistor in which the channel was prepared by reactive sputtering of a ZnO target.

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“…1 c through the transient curve. Oxide semiconductors have the problem of persistent photocurrent (PPC), which is increased dark current under periodic light signals caused by ionized oxygen vacancies (V o 2+ ) during the photoresponse 22 . The RF-PTs maintained a photocurrent and did not show a PPC phenomenon during repeated photoresponse.…”

Section: Resultsmentioning

confidence: 99%

Enhanced performance and stability in InGaZnO NIR phototransistors with alumina-infilled quantum dot solid

Kim

Shin

et al. 2022

Sci Rep

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The optimized ALD infilling process for depositing Al2O3 in the vertical direction of PbS QDs enhances the photoresponsivity, relaxation rate and the air stability of PbS QDs hybrid IGZO NIR phototransistors. Infilled Al2O3, which is gradually deposited from the top of PbS QDs to the PbS/IGZO interface (1) passivates the trap sites up to the interface of PbS/IGZO without disturbing charge transfer and (2) prevents QDs deterioration caused by outside air. Therefore, an Al2O3 infilled PbS QD/IGZO hybrid phototransistor (AI-PTs) exhibited enhanced photoresponsivity from 96.4 A/W to 1.65 × 102 A/W and a relaxation time decrease from 0.52 to 0.03 s under NIR light (880 nm) compared to hybrid phototransistors without Al2O3 (RF-PTs). In addition, AI-PTs also showed improved shelf stability over 4 months compared to RF-PTs. Finally, all devices we manufactured have the potential to be manufactured in an array, and this ALD technique is a means of fabricating robust QDs/metal oxide hybrids for optoelectronic devices.

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Reduction of Persistent Photoconduction with IGZO/ZnON-Tandem-Structure Visible–Near-Infrared Phototransistors

Cited by 7 publications

References 27 publications

Ultrasensitive Near‐Infrared InAs Colloidal Quantum Dot‐ZnON Hybrid Phototransistor Based on a Gradated Band Structure

Ultrasensitive Near‐Infrared InAs Colloidal Quantum Dot‐ZnON Hybrid Phototransistor Based on a Gradated Band Structure

In Situ IGZO/ZnON Phototransistor Free of Persistent Photoconductivity with Enlarged Spectral Responses

Enhanced performance and stability in InGaZnO NIR phototransistors with alumina-infilled quantum dot solid

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