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The low-cost ultraviolet photodetectors (UV PDs) with high performance have wide applications in many important fields, herein, both well-aligned zinc oxide nanowire arrays (ZNWAs) and gallium (Ga)-doped ZNWAs (GZNWAs, Ga/Zn = 1 atom%) UV PDs were fabricated by a hydrothermal technique, their performances were analyzed in detail. The results showed that the GZNWAs UV PD exhibited an excellent response to 365 nm light, its response time (T r), decay time (T d), responsivity (R λ), sensitivity (S), detectivity (D⁎) and external quantum efficiency (EQE) were 9.8 s, 45.8 s, 72.8 A/W at 5 V, 747.8 at 0 V, 5.5 × 1012 Jones and 2.5 × 104%, respectively. By comparison, the performances of GZNWAs UV PD were much better than those of ZNWAs UV PD, we found that Ga doping played a key role on improving the performances of ZNWAs-based UV PDs The photocurrents of ZNWAs and GZNWAs ultraviolet photodetectors can be reproducibly switched from the 'ON' state to the 'OFF' state with a stable state by periodically turning UV light on and off under 71 μW/cm2 365 nm light irradiation at 5 V bias. [Display omitted] • A low-cost and high-performance GZNWAs UV PD was fabricated. • The GZNWAs UV PD showed good response to 365 nm light. • The performance of GZNWAs UV PD was investigated in detail. • The GZNWAs UV PD had better performances than the ZNWAs UV PD. [ABSTRACT FROM AUTHOR]

The high-performance, low-cost and simple ultraviolet photodetectors are very promising in some applications. Here, single-crystalline zinc oxide (ZnO) nanoflowers were prepared by combining a facile hydrothermal method with post-annealing treatment, we built an ultraviolet photodetector with an active area of 0.36 cm2 using the as-prepared ZnO nanoflowers. The results showed that under 365 nm light illumination with a light intensity of 77 μW/cm2, the sensitivity, response time, decay time, responsivity and gain of the device were 19991.3 (−0.1 V), 16.4 s, 37.6 s, 9.0 A/W (5 V) and 30.6 (5 V), respectively, indicating that a ZnO nanoflowers UV photodetector with superhigh sensitivity was achieved. At a bias of 2 V, the photocurrent of the ZnO nanoflowers UV photodetector can be reproducibly switched from the 'ON' state to the 'OFF' state with a very stable state by periodically turning UV light (365 nm, 77 μW/cm2) on and off.▪ • The ZnO nanoflowers were prepared by combining a facile method. • The ZnO nanoflowers are single crystalline. • A low-cost ultraviolet photodetector with simple structure was fabricated. • The fabricated ultraviolet photodetector had a superhigh sensitivity of 19991.3. [ABSTRACT FROM AUTHOR]

At a bias of 2 V, the photocurrent of the ZnO quantum dots ultraviolet photodetector can be reproducibly switched from the 'ON' state to the 'OFF' state with a very stable state by periodically turning UV light (365 nm) on and off with a power density of 48 μW/cm2. • ZnO quantum dots were synthesized by a facile method. • A low-cost and solution-processed ultraviolet photodetector was fabricated. • The ultraviolet photodetector could operate at very low voltage. • The ultraviolet photodetector exhibited a high responsivity and rapid response. Solution-processed zinc oxide (ZnO) ultraviolet (UV) photodetector with high performance has great potential in practical applications. In this letter, ZnO quantum dots with diameters ranged in 4–6 nm were synthesized by a facile solution method. The results showed that the as-synthesized quantum dots were wurtzite structured ZnO and had specific surface area as high as 68.3 m2/g. Also, a solution-processed ZnO quantum dots-based ultraviolet photodetector was built. This UV photodetector exhibited a good photoresponse to 365 nm UV light at low operating voltage, under 48 μW/cm2 UV illumination, the responsivity (R), photocurrent gain (G), response time (T r) and decay time (T d) of the photodetector were 21.6 A/W at 3.6 V, 85.8 at 4.0 V, 1.9 s and 51.1 s, respectively. [ABSTRACT FROM AUTHOR]