ORCID Profile
0000-0002-5433-4124
Current Organisation
Bangladesh University of Engineering and Technology
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Publisher: IOP Publishing
Date: 03-2015
Publisher: Springer Science and Business Media LLC
Date: 05-03-2019
DOI: 10.1038/S41598-019-40029-3
Abstract: Undoped and Ga-doped ZnO films were grown on c-sapphire using pulsed laser deposition (PLD) at the substrate temperature of 600 °C. Positron annihilation spectroscopy study (PAS) shows that the dominant V Zn -related defect in the as-grown undoped ZnO grown with relative low oxygen pressure P(O 2 ) is a vacancy cluster (most likely a V Zn -nV O complex with n = 2, 3) rather than the isolated V Zn which has a lower formation energy. Annealing these s les at 900 °C induces out-diffusion of Zn from the ZnO film into the sapphire creating the V Zn at the film/sapphire interface, which favors the formation of vacancy cluster containing relatively more V Zn . Increasing the P(O 2 ) during growth also lead to the formation of the vacancy cluster with relatively more V Zn . For Ga-doped ZnO films, the oxygen pressure during growth has significant influence on the electron concentration and the microstructure of the V Zn -related defect. Green luminescence (GL) and yellow luminescence (YL) were identified in the cathodoluminescence study (CL) study, and both emission bands were quenched after hydrogen plasma treatment. The origin of the GL is discussed.
Publisher: Elsevier BV
Date: 05-2010
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 09-2020
Publisher: AIP Publishing
Date: 20-03-2017
DOI: 10.1063/1.4978761
Abstract: Undoped and Ga-doped ZnO nanorods both exhibit an intense green luminescence (GL) band centered at ∼2.4 eV. Unlike the defect-related GL in undoped nanorods, the GL band in Ga-doped nanorods displays a periodic fine structure separated by 72 meV, which consists of doublets with an energy spacing of 30 ± 3 meV. The emergence of the structured GL is due to the Cu+ state being stabilized by the rise in the Fermi level above the 0/- (Cu2+/Cu+) charge transfer level as a result of Ga donor incorporation. From a combination of optical characterization and simulation using the Brownian oscillator model, the doublet fine structures are shown to originate from two hole transitions with the Cu+ state located at 390 meV above the valence band.
Publisher: Wiley
Date: 19-06-2018
Publisher: Elsevier BV
Date: 02-2022
Publisher: IOP Publishing
Date: 12-06-2014
Publisher: IOP Publishing
Date: 17-08-2018
Abstract: Bottom-up fabrication of nanowire-based devices is highly attractive for oxide photonic devices because of high light extraction efficiency however, unsatisfactory electrical injection into ZnO and poor carrier transport properties of nanowires severely limit their practical applications. Here, we demonstrate that ZnO nanorods doped with Ga donors by in situ dopant incorporation during vapour-solid growth exhibit superior optoelectronic properties that exceed those currently synthesised by chemical vapour deposition, and accordingly can be electrically integrated into Si-based photonic devices. Significantly, the doping method was found to improve the nanorod quality by decreasing the concentration of point defects. Light-emitting diodes (LEDs) fabricated from the Ga-doped ZnO nanorod -Si heterojunction display bright and colour-tunable electroluminescence (EL). These nanorod LEDs possess a dramatically enhanced performance and an order of magnitude higher EL compared with equivalent devices fabricated with undoped nanorods. These results point to an effective route for large-scale fabrication of conductive, single-crystalline ZnO nanorods for photonic and optoelectronic applications.
Publisher: American Chemical Society (ACS)
Date: 17-02-2022
Publisher: Elsevier BV
Date: 2017
Publisher: IEEE
Date: 05-2012
Publisher: Elsevier BV
Date: 08-2014
Publisher: IOP Publishing
Date: 28-10-2014
Publisher: American Chemical Society (ACS)
Date: 22-08-2023
Publisher: Elsevier BV
Date: 11-2014
Publisher: Springer Science and Business Media LLC
Date: 11-06-2019
Publisher: American Chemical Society (ACS)
Date: 17-02-2022
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 07-2019
Publisher: IOP Publishing
Date: 23-01-2014
Publisher: Science Publishing Group
Date: 2014
Location: Bangladesh
No related grants have been discovered for Dr. Md. Azizar Rahman.