Fast Photoresponse and Long Lifetime UV Photodetectors and Field Emitters Based on ZnO/Ultrananocrystalline Diamond Films

Abstract

We have designed photodetectors and UV field emitters based on a combination of ZnO nanowires/nanorods (ZNRs) and bilayer diamond films in a metal-semiconductor-metal (MSM) structure. The ZNRs were fabricated on different diamond films and systematic investigations showed an ultra-high photoconductive response from ZNRs prepared on ultrananocrystalline diamond (UNCD) operating at a lower voltage of 2 V. We found that the ZNRs/UNCD photodetector (PD) has improved field emission properties and a reduced turn-on field of 2.9 V μm(-1) with the highest electron field emission (EFE) by simply illuminating the sample with ultraviolet (UV) light. The photoresponse (Iphoto /Idark ) behavior of the ZNRs/UNCD PD exhibits a much higher photoresponse (912) than bare ZNRs (229), ZNRs/nanocrystalline diamond (NCD; 518), and ZNRs/microcrystalline diamond (MCD; 325) under illumination at λ=365 nm. A photodetector with UNCD films offers superior stability and a longer lifetime compared with carbon materials and bare ZNRs. The lifetime stability of the ZNRs/UNCD-based device is about 410 min, which is markedly superior to devices that use bare ZNRs (92 min). The ZNRs/UNCD PD possesses excellent photoresponse properties with improved lifetime and stability; in addition, ZNRs/UNCD-based UV emitters have great potential for applications such as cathodes in flat-panel displays and microplasma display devices.

Enhanced optoelectronic performances of vertically aligned hexagonal boron nitride nanowalls-nanocrystalline diamond heterostructures

“…A myriad of heterostructured materials have been developed. Heterostructures such as single-walled CNTs–CdSe quantum dots 18 , SnO 2 -CNTs 19 , MoS 2 –WS 2 20 , CNT-graphene 21 , gold–ultrananocrystalline diamond (UNCD) 22 , BN–graphene 23 , CNT–UNCD on Si tips 24 , ZnO nanopillars–Si 25 , ZnO nanorods–UNCD 26 , graphene-nanodiamond 27 , InAs–GaAs nanowires 28 , TiSi 2 nanonets–Si nanostructures 29 have been extensively studied. Fabrication of such heterostructures is not only vital for fundamental studies but also for diverse advanced functional devices, for instance, interconnects and emitters, etc.…”

High‐Performance Sensor Based on Thin‐Film Metallic Glass/Ultra‐nanocrystalline Diamond/ZnO Nanorod Heterostructures for Detection of Hydrogen Gas at Room Temperature

“…We also observed av ery smallp eak (marked by^)a t4 3.88 attributable to the diamondd iffraction peak of the (111)p lane;h owever,i t did not appear in the pure ZNR. [17] As shown in the Figure 3, the (0 02)d iffractionp eaks exhibited the highest intensity, therebyc onfirming that the ZNRs were well-oriented and that the nanorods grew along the (0 001) direction. [22] Figure 3b presents representative Raman spectra of the asprepared Z, DZ, and MDZ samples.T he active dominant peaks of ZnO at 100 and 437 cm À1 can be, respectively,a ttributed to the low-E2 and high-E2v ibrational modes of nonpolaro ptical phonons.…”

“…This proffers additional trapping centers, which promote the injec-tion of additional free electrons from the conduction band. [17][18][19] In contrast, thin-film metallic glasses (TFMG), also known as amorphous metallic alloys, are ac lass of materials with disordered structures exhibitingu nique properties often surpassing those of conventional materials. Most metallicg lasses consist of transition metals,a nd are commonly formed by quenching al iquidusm elt.…”

“…Moreover, UNCD films have higher conduction and valence band edges than do ZNRs. This proffers additional trapping centers, which promote the injection of additional free electrons from the conduction band …”

Structural Engineering of Dispersed Graphene Flakes into ZnO Nanotubes on Discontinues Ultra‐Nanocrystalline Diamond Substrates for High‐Performance Photodetector with Excellent UV Light to Dark Current Ratios

“…[1] Especially, graphene (Gr) is an excellent and most famous 2D thin-layered carbon material that possesses excellent electrical conductivity, mobility, superior mechanical enhanced photocarrier lifetime, and also metallization effect, thereby making it as one of promising UV photodetections hybrids. [11] Among the many 1D nano-semiconductors, ZnO is very promising and environment-friendly materials with wide bandgap of 3.37 eV. [11] Among the many 1D nano-semiconductors, ZnO is very promising and environment-friendly materials with wide bandgap of 3.37 eV.…”