Broad-Band High-Sensitivity ZnO Colloidal Quantum Dots/Self-Assembled Au Nanoantennas Heterostructures Photodetectors

Abstract

Tunable plasmonic resonance induced by the collective oscillation of the electrons on metallic nanostructures can excellently enhance the light response of ZnO films, which provides an effective way to break through the limitation of the performance of ZnO photodetectors. Here, broad-band high-performance ZnO/Au heterostructures photodetectors with various morphologies of self-assembled Au nanoantennas are fabricated via a facile approach under the spin-coated ZnO colloidal quantum dots films. With a systematic control on growth condition, the self-assembled Au nanoantennas undergo a drastic evolution from the corrugated nanomounds to the island-like nanostructures, and the light absorption of the resulting ZnO/Au heterostructures correspondingly exhibits a strongly morphological dependence on the Au nanoantennas. Meanwhile, the photoresponse of the ZnO-based photodetectors is significantly improved throughout a wide spectrum between UV and visible regions owing to the enhanced light absorption induced by the localized surface plasmon resonance. As a result, the optimal switch ratio of the ZnO/Au heterostructures photodetector increases by 1 order to ∼1.13 × 10 than that of the pristine ZnO one because of the obviously increased photocurrent ( I) and comparable dark current, thus leading to ∼9.1 and ∼4.9 times increases in the photoresponsivity and the normalized detectivity. Meanwhile, the significant increases in the I of ∼5.2 and ∼9.7 times are likewise observed with the ZnO/Au heterostructures under 530 nm and white-light illumination. This work can offer a handy and effective approach for the fabrication of ultrasensitive ZnO-based photodetectors within a broad-band wavelength by utilizing the Au plasmonic nanostructures.

Improved Photoresponse of UV Photodetectors by the Incorporation of Plasmonic Nanoparticles on GaN Through the Resonant Coupling of Localized Surface Plasmon Resonance

“…In specific, the photocurrent of bare GaN, Ag, and Au reached up to 3.56 × 10 –4 , 9.97 × 10 –4 , and 1.61 × 10 –3 A, respectively, at 0.1 V and 10.36 mW mm −2 . The integration of Ag and Au NPs on the bare GaN photodetector demonstrated a strong contribution toward photocurrent enhancement due to the LSPR effect [ 29 , 42 ]. At the same time, it was also observed that the Au NPs induced much larger photocurrent as compared to the Ag NPs, which suggests the morphological and elemental dependence of LSPR in the photocurrent enhancement.…”

“…The R is defined as the ratio of photocurrent generated to illuminated optical power intensity and expressed as Eq. 2 [29]:…”

“…However, the detailed study on the application of plasmonic AgAu alloy NPs in the UV photodetectors has not been attempted up to now. The Ag and Au NPs have shown excellent optical absorption, scattering, electromagnetic near-field, and charge transfer characteristics due to their strong LSPR effect in the UV-Vis regions [27][28][29]. Generally, the LSPR of Ag NPs is in the shorter wavelength (< 430 nm) as compared to the Au NPs (> 530 nm).…”

Journey of ZnO quantum dots from undoped to rare-earth and transition metal-doped and their applications

“…The photoresponse of the ZnO QD-based photodetectors can also be increased with the aid of localized surface plasmon resonance (LSPR). [160][161][162] In this technique, novel metal nanoparticles are fabricated over the sensing material. In such a case, a nearsurface electric eld is formed due to the collective oscillation of electrons on the surface nanoparticles, which ultimately increases the absorption of light.…”

Ultrahigh Responsivity UV Photodetector Based on Cu Nanostructure/ZnO QD Hybrid Architectures

“…Hybrid Architecture Photodetectors Fabrication : ZnO colloidal quantum dots (CQDs) were initially synthesized by the solvothermal method, and spin‐coated on glass substrates. Briefly, 1.29 g of potassium hydroxide (KOH, 85%, Aladdin, CAS: 1310‐58‐3) was dissolved into 23 mL of methanol, and then gradually dropped into 126 mL zinc acetate (2.94 g, Zn(CH 3 COO) 2 , 99.99%, Aladdin, CAS: 5970‐45‐6) methanol solution (CAS: 67‐56‐1).…”