Synthesis of ZnO nanorods by microwave-assisted chemical-bath deposition for highly sensitive self-powered UV detection application

Abstract

High-quality vertically aligned zinc oxide (ZnO) nanorods were successfully grown on seeded silicon substrates p-Si(100) through microwave-assisted chemical bath deposition. Structural and morphological analyses revealed hexagonal wurtzite nanorods perpendicular to the substrate along the c-axis in the direction of the (002) plane. Optical measurements showed a high-intensity UV peak with a low broad visible peak. UV emission was compared with the visible emission having an IUV/Ivis ratio of 53. A metal-semiconductor-metalbased UV detector was then fabricated by depositing two metal contacts onto the ZnO nanorod surfaces. Current-voltage measurements revealed a highly sensitive device with a self-powered characteristic. At zero applied bias, the fabricated device showed a significant difference between the UV current and dark current. The device further showed a sensitivity of 304 × 104 to low-power (1.5 mW/cm2) 365 nm light pulses without an external bias. Photoresponse measurements demonstrated the highly reproducible characteristics of the fabricated UV detector with rapid response and baseline recovery times of 10 ms. This work introduced a simple, low-cost method of fabricating rapid-response, highly photosensitive UV detectors with zero power consumption.

High responsivity and 1/f noise of an ultraviolet photodetector based on Ni doped ZnO nanoparticles

“…For the responsivity performance, the stability Schottky barriers height play an important role. 43 Also, the existence of strong depletion width could make influence in the responsivity improvement. It can be observed that the maximum responsivity of the device is 300 mA W −1 at 4.5 V applied bias.…”

“…This value of responsivity is larger than the value reported by Pei 44 and as comparable to ZnO PDs reported by other groups. 43,45 P. S. Shewale et al 46 reported the highest value of responsivity for Ti doped ZnO PDs about 50 mA W À1 . Our photocurrent measurements allowed us to determine the quantum efficiency that corresponds to the number of electron-hole pairs generated by incident photon, it expressed by:…”

Optimization of ZnO Nanorods Concentration in a Micro-Structured Polymeric Composite for Nanogenerators

“…One interesting method is the hydrothermal synthesis under microwave radiation since it is a low-cost, low-temperature, and fast method, yet allowing a high yield production of hexagonal wurtzite structures [46,64]. Despite the advantages, ZnO NRs produced through this method have been essentially explored for UV sensors [46,51,65,66], gas sensors [67][68][69][70], and photocatalysis [49,71,72], yet not for NGs.…”

Morphology Transition of ZnO Nanorod Arrays Synthesized by a Two-Step Aqueous Solution Method

“…Among them, ZnO, as an important II-VI semiconductor with a direct band gap of 3.37 eV, larger exciton binding energy of 60 mV [9,10] at room temperature, and piezoelectricity [11], has attracted special interest. Especially, vertically aligned ZnO nanorod arrays (ZNAs), due to their non-toxicity, low-cost, large surface to volume ratio, and ease of large scale fabrication, can be employed in many devices, like solar cells, UV lasers, gas sensors, UV detectors, and photocatalysis [12][13][14][15][16][17][18][19][20]. Various methods have been used to synthesize ZNAs, including chemical vapor deposition (CVD) [21,22], pulsed laser deposition (PLD) [23], molecular beam epitaxy (MBE) [10,24], etc.…”