Tuning of deep level emission in highly oriented electrodeposited ZnO nanorods by post growth annealing treatments

2014 ◽  
Vol 116 (7) ◽  
pp. 074309 ◽  
Author(s):  
A. Simimol ◽  
N. T. Manikandanath ◽  
Aji A. Anappara ◽  
Prasanta Chowdhury ◽  
Harish C. Barshilia
Keyword(s):  
Deep Level ◽  
Zno Nanorods ◽  
Deep Level Emission

Growth of Well-Aligned ZnO Nanorods Using AuGe Catalyst by Vapor Phase Transportation

2006 ◽  
Vol 6 (11) ◽  
pp. 3624-3627
Author(s):  
S. Y. Ha ◽  
M. N. Jung ◽  
S. H. Park ◽  
H. J. Ko ◽  
H. Ko ◽  
...  
Keyword(s):  
Deep Level ◽  
Zno Nanorods ◽  
Horizontal Tube ◽  
Deep Level Emission ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Uv Emission ◽  
Tilting Angle

Well-aligned ZnO nanorods have been achieved using new alloy (AuGe) catalyst. Zn powder was used as a source material and it was transported in a horizontal tube furnace onto an AuGe deposited Si substrates. The structural and optical properties of ZnO nanorods were characterized by scanning electron microscopy, high resolution X-ray diffraction, and photoluminescence. ZnO nanorods grown at 650 °C on 53 nm thick AuGe layer show uniform shape with the length of 8±0.5 μm and the diameter of 150±5 nm. Also, the tilting angle of ZnO nanorods (±5.5°) is confirmed by HRXRD. High structural quality of the nanorods is conformed by the photoluminescence measurement. All samples show strong UV emission without considerable deep level emission. However, weak deep level emission appears at high (700 °C) temperature due to the increase of oxygen desertion.

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

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1067 ◽  
Author(s):  
Hafiz Muhammad Salman Ajmal ◽  
Fasihullah Khan ◽  
Noor Ul Huda ◽  
Sunjung Lee ◽  
Kiyun Nam ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Electronic Device ◽  
Deep Level ◽  
Zno Nanorods ◽  
Ultra Violet ◽  
Device Fabrication ◽  
Electrode Structure ◽  
Large Area ◽  
X Ray

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 R 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. The doping with Ni/Cu or Cu not only improves the crystalline quality but also significantly suppresses the density of deep-level emission defects in as-grown ZnO nanorods, as demonstrated by X-ray diffraction and photoluminescence. Furthermore, the X-ray photoelectron spectroscopy analysis shows that doping with the transition metals significantly increases the oxygen bonding with metal ions with enhanced O/Zn stoichiometry in as-grown nanorods. The fabricated flexible PD devices based on an interdigitated electrode structure demonstrates a very high R of ~123 A/W, a high on-off current ratio of ~130, and a significant improvement in transient response speed exhibiting rise and fall time of ~8 and ~3 s, respectively, by using the ZnO nanorods codoped by Ni/Cu.

Electrical and Optical Characterisation of Homojjunction Gallium Nitride Light Emitting Diodes

1997 ◽  
Vol 482 ◽  
Author(s):  
G M Laws ◽  
J Morgan ◽  
G B Ren ◽  
I Harrison ◽  
E C Larkins ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Full Width Half Maximum ◽  
Light Emitting Diodes ◽  
Deep Level ◽  
Deep Level Emission ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Light Emitting ◽  
Current Voltage ◽  
Current Voltage Characteristics

AbstractWe report on the fabrication and characterisation gallium nitride light emitting diodes (LEDs) grown by molecular beam epitaxy on (0001) oriented sapphire and (111)B GaAs substrates. The current voltage characteristics of the devices grown on sapphire show turn on voltages of between 4 and 5V with large on-series resistance of 600Ω; for corresponding devices grown on GaAs these parameters are between 6 and 7V and 150 Ω, respectively.Room temperature electroluminescence (EL) spectra from the GaN LEDs ,grown on sapphire substrates, show a dominant emission at 3.2 eV (397nm) with a full width half maximum (FWHM) of 335 meV which is attributed to free electron to acceptor transitions (e, A−Mg). A broad low intensity deep level emission is also observed centred at 2.4 eV (506nm). The peak of the EL from the devices grown on GaAs is at 3.1eV rather than 3.2eV. The differences between the two sets of devices are probably caused by the different device geometry.Preliminary results show that an “annealing” effect caused by electrical stressing resulted in an improvement of the EL spectra. The stressed samples show an increase in the near band edge emission intensity, a 20meV reduction in the FWHM and a significant reduction in the intensity of the deep level emission. The devices have a large 1/f noise contribution which does not appear to change after electrical stressing.

scholarly journals Deep level emission of ZnO nanoparticles deposited inside UV opal

2006 ◽  
Vol 259 (1) ◽  
pp. 378-384 ◽  
Author(s):  
S.M. Abrarov ◽  
Sh.U. Yuldashev ◽  
T.W. Kim ◽  
Y.H. Kwon ◽  
T.W. Kang
Keyword(s):  
Zno Nanoparticles ◽  
Deep Level ◽  
Deep Level Emission

A comparative analysis of deep level emission in ZnO layers deposited by various methods

2009 ◽  
Vol 105 (1) ◽  
pp. 013502 ◽  
Author(s):  
Cheol Hyoun Ahn ◽  
Young Yi Kim ◽  
Dong Chan Kim ◽  
Sanjay Kumar Mohanta ◽  
Hyung Koun Cho
Keyword(s):  
Comparative Analysis ◽  
Deep Level ◽  
Deep Level Emission

Tunable deep-level emission in ZnO nanoparticles via yttrium doping

2011 ◽  
Vol 509 (8) ◽  
pp. 3606-3612 ◽  
Author(s):  
Jinghai Yang ◽  
Rui Wang ◽  
Lili Yang ◽  
Jihui Lang ◽  
Maobin Wei ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Deep Level ◽  
Deep Level Emission ◽  
Yttrium Doping

scholarly journals Improved Ultraviolet Photoresponse Properties of ZnO Nanorods Grown by Using Hydrothermal Method Applied Rotating Precursor Solution

2021 ◽  
Vol 59 (3) ◽  
pp. 187-194
Author(s):  
Dongwan Kim ◽  
Jae-Young Leem
Keyword(s):  
Surface Modification ◽  
Hydrothermal Method ◽  
Rotation Rate ◽  
Deep Level ◽  
Zno Nanorods ◽  
Precursor Solution ◽  
Near Band Edge ◽  
High Reproducibility ◽  
Axis Orientation ◽  
Diffraction Peaks

We grew ZnO nanorods (NRs) using a hydrothermal method while rotating the precursor solution, and report the effect of rotation on surface modification, and the optical and ultraviolet (UV) photoresponse properties of the resulting ZnO nanorods. The ZnO NRs grown in the rotating precursor solution at 100 rpm had the longest length and diameter, which decreased with increasing rotation rate above 100 rpm. Also, the intensity of the diffraction peaks from ZnO (002) and (100) was strongest and weakest for the ZnO NRs grown in a rotating solution at 150 rpm, respectively, indicating improvement in the c-axis orientation of the ZnO NRs. In the PL spectra, near-band-edge (NBE) and deep-level (DL) emissions were observed from all of the ZnO NRs. The intensity of the NBE emission gradually increased with increasing rotation rate, due to the increase in surface area. Also, the intensity of the DL emission gradually increased with increasing rotation rate because of the increasing number of interstitial oxygens. Analysis of the UV photoresponse found the photocurrent of the ZnO NRs grown in the rotating precursor solution was higher than that of ZnO NRs grown in a non-rotated precursor solution. In particular, ZnO NRs grown in a rotating precursor solution at 150 rpm exhibited the highest value of photosensitivity, with high reproducibility.

Sign in / Sign up

Export Citation Format

Share Document