Role of Seed Layer Crystalline Quality in Photoresponse Performance of Hydrothermally Grown ZnO Nanorods.

We investigated the effects of the crystalline state for seed layers (SLs) on the growth morphology and material characteristics for hydrothermally grown ZnO nanorods (NRs). For this, preheating (PH) at different temperatures (100-300 °C) and O plasma treatment (PT) for 9 min were performed during the growth of SLs on p-Si by the aqueous solution-based method to provide the characteristic change on the NR growth platform. An improvement in material properties was achieved from the ZnO NRs grown on the SL crystals of enhanced crystalline quality in terms of the increased preferred orientation (002), the higher UV emission with suppressed deep-level emissions, the recovery of O/Zn stoichiometry, and the reduction of various intrinsic defects.

Effects of Seed-Layer NO Plasma Treatment on ZnO Nanorod Based Ultraviolet Photodetectors: Experimental Investigation with Two Different Device Structures.

The crystalline quality of ZnO NR (nanorod) as a sensing material for visible blind ultraviolet PDs (photodetectors) critically depends on the SL (seed layer) material of properties, which is a key to high-quality nanocrystallite growth, more so than the synthesis method. In this study, we fabricated two different device structures of a gateless AlGaN/GaN HEMT (high electron mobility transistor) and a photoconductive PD structure with an IDE (interdigitated electrode) pattern implemented on a PET (polyethylene terephthalate) flexible substrate, and investigated the impact on device performance through the SL NO plasma treatment. In case of HEMT-based PD, the highest current on-off ratio (~7) and spectral responsivity (~1.

Enhancement in the photonic response of ZnO nanorod-gated AlGaN/GaN HEMTs with N2O plasma treatment.

We demonstrate an improvement in the photoresponse characteristics of ultraviolet (UV) photodetectors (PDs) using the NO plasma-treated ZnO nanorod (NR) gated AlGaN/GaN high electron mobility transistor (HEMT) structure. The PDs fabricated with ZnO NRs plasma-treated for 6 min show superior performance in terms of responsivity (∼1.54×10 A/W), specific detectivity (∼ 4.

Ultraviolet Photodetection Based on High-Performance Co-Plus-Ni Doped ZnO Nanorods Grown by Hydrothermal Method on Transparent Plastic Substrate.

A growth scheme at a low processing temperature for high crystalline-quality of ZnO nanostructures can be a prime stepping stone for the future of various optoelectronic devices manufactured on transparent plastic substrates. In this study, ZnO nanorods (NRs) grown by the hydrothermal method at 150 °C through doping of transition metals (TMs), such as Co, Ni, or Co-plus-Ni, on polyethylene terephthalate substrates were investigated by various surface analysis methods. The TM dopants in ZnO NRs suppressed the density of various native defect-states as revealed by our photoluminescence and X-ray photoelectron spectroscopy analysis.

High-Performance Flexible Ultraviolet Photodetectors with Ni/Cu-Codoped ZnO Nanorods Grown on PET Substrates.

As a developing technology for flexible electronic device fabrication, ultra-violet (UV) photodetectors (PDs) based on a ZnO nanostructure are an effective approach for large-area integration of sensors on nonconventional substrates, such as plastic or paper. However, photoconductive ZnO nanorods grown on flexible substrates have slow responses or recovery as well as low spectral responsivity because of the native defects and inferior crystallinity of hydrothermally grown ZnO nanorods at low temperatures. In this study, ZnO nanorod crystallites are doped with Cu or Ni/Cu when grown on polyethylene terephthalate (PET) substrates in an attempt to improve the performance of flexible PDs.