J.H. Heo

Effects of precursor concentration on ZnO nanorods grown on flexible PET substrate by hydrothermal synthesis

In this study, the effects of precursor concentration on the zinc oxide (ZnO) nanorods grown on flexible polyethylen terephthalate (PET) substrate with and without buffer layer were discussed. The concentration was varied from 0.05 to 0.5M. When we inserted buffer layer before hydrothermally growth of ZnO, better aligned ZnO nanorods were grown. At relatively middle concentration (from 0.2 to 0.3M), well-aligned ZnO nanorods were grown on PET substrate with and without buffer layer. The crystal structural properties and surface morphologies were examined by x-ray diffraction (XRD), and field emission scanning electron microscope (FE-SEM), respectively.

Dependence of the Heterojunction Diode Characteristics of ZnO/ZnO/p-Si(111) on the Buffer Layer Thickness

In this study, the effects of an annealed buffer layer with different thickness on heterojunction diodes based on the ZnO/ZnO/p-Si(111) systems were reported. The effects of an annealed buffer layer with different thickness on the structural, optical, and electrical properties of zinc oxide (ZnO) films on p-Si(111) were also studied. Before zinc oxide (ZnO) deposition, different thicknesses of ZnO buffer layer, 10 nm, 30 nm, 50 nm and 70 nm, were grown on p-Si(111) substrates using a radio-frequency sputtering system; samples were subsequently annealed at for 10 minutes in in a horizontal thermal furnace. Zinc oxide (ZnO) films with a width of 280nm were also deposited using a radio-frequency sputtering system on the annealed ZnO/p-Si (111) substrates at room temperature; samples were subsequently annealed at for 30 minutes in . In this experiment, the structural and optical properties of ZnO thin films were studied by XRD (X-ray diffraction), and room temperature PL (photoluminescence) measurements, respectively. Current-voltage (I-V) characteristics were measured with a semiconductor parameter analyzer. The thermal tensile stress was found to decrease with increasing buffer layer thickness. Among the ZnO/ZnO/p-Si(111) diodes fabricated in this study, the sample that was formed with the condition of a 50 nm thick ZnO buffer layer showed a strong c-axis preferred orientation and I-V characteristics suitable for a heterojunction diode.

Dependence of the Diode Characteristics of ZnO/b-ZnO/p-Si(111) on the Buffer Layer Thickness and Annealing Temperature

In this study, the effects of ZnO buffer layer thickness and annealing temperature on the heterojunction diode, ZnO/b-ZnO/p-Si(111), were reported. The effects of those on the structural and electrical properties of zinc oxide (ZnO) films on ZnO buffered p-Si (111) substrate were also studied. Structural properties of ZnO thin films were studied by X-ray diffraction and I-V characteristics were measured by a semiconductor parameter analyzer. ZnO thin films with 70 nm thick buffer layer and annealing temperature of showed the best c-axis preferred orientation. The best electrical property was found at the condition of buffer layer annealing temperature of and 50nm thick ZnO buffer layer (resistivity: , carrier concentration: ). The I-V characteristics for ZnO/b-ZnO/p-Si(111) heterojunction diode were improved with increasing buffer layer thickness at buffer layer annealing temperature of .

Effects of O 2 plasma power on the structural and surface morphologies of ZnO thin films grown on the flexible PES substrate by atomic layer deposition

ZnO thin films were deposited on polyethersurfone (PES) substrates by atomic layer deposition (ALD). We investigated the effects of O2 plasma pretreatment from 0W to 100W before the ZnO growth. When the plasma power was increased, the PET substrate surface roughness was also increased. However, the surface roughness of ZnO on the roughest PET substrate with maximum plasma power pretreatment showed the smoothest value. The XRD (002) peak intensity of ZnO was increased with increasing plasma power. The morphologies of ZnO thin films were measured by atomic force microscope (AFM) and scanning electron microscope (SEM). And the crystal structural properties were analyzed by x-ray diffraction (XRD) method.