12-03-2014, 04:56 PM
Synthesis and characterization of well-aligned Zn1ÀxMgxO nanorods and film by metal organic chemical vapor deposition
[attachment=60080]
ABSTRACT
Well-aligned Zn1ÀxMgxO nanorods and film with Mg-content x from 0 to 0.051 have been successfully
synthesized by metal organic chemical vapor deposition (MOCVD) without any catalysts. The
characterization results showed that the diameters and lengths of the nanorods were in the range
of 20–80 nm and 330–360 nm, which possessed wurtzite structure with a c-axis growth direction.
As the increase of Mg precursor flows into the growth chamber, the morphology of Zn1ÀxMgxO evolves
from nanorods to a film with scale-like surface and the height of the nanorods and the film was almost
identical, it is suggested that the growth rate along the c-axis was hardly changed while the growth of
̄ 0} of the Zn1ÀxMgxO has been improved. Photoluminescence and
six equivalent facets of the type {1 0 1
Raman spectra show that the products have a good crystal quality with few oxygen vacancies. With the
Mg incorporation, multiple-phonon scattering become weak and broad, and the intensities of all
observed vibrational modes decrease. And the ultraviolet near-band-edge emission shows a clear
blueshift (x=0.051, as much as 90 meV) and slightly broadening compared with that of pure ZnO
nanorods.
Introduction
One-dimensional (1D) nanostructures of semiconductors have
stimulated great interest due to their importance in scientific
research and potential utilization in optical and electronic devices
[1,2]. Among these nanostructures, ZnO nanowires have drawn
considerable interests as building blocks or basic units for the
fabrication of nanosized devices due to a wide and direct
fundamental bandgap energy of 3.37 eV and a large exciton
binding energy (60 meV) with high mechanical and thermal
stability. Two critical challenges in fabricating ZnO laser diodes
are p-type doping [3–5] and band gap engineering in alloy
semiconductors to create barrier layers and quantum wells which
facilitate radiative recombination by carrier confinement.
Zn1ÀxMgxO, which is realized by alloying ZnO with Mg (permitting
the band gap to be tuned from 3.3 to 7.8 eV for wurtzite- and
cubic-structured Zn1ÀxMgxO [6–8])
Summary
In summary, we have prepared well-aligned Zn1ÀxMgxO
nanorods and film with tunable optical properties by MOCVD
without any catalysts by varying the composition of Mg. The mean
diameters and lengths of the nanorods were in the range of
20–80 nm and 330–360 nm. As the increase of Mg precursor flows
into the growth chamber, the morphology of Zn1ÀxMgxO evolves
from nanorods to a film with scale-like surface. PL and Raman
spectra show that the nanorods and film have a good crystal
quality with few oxygen vacancies. And the UV NBE emission
shows a clear blueshift (x=0.051, as much as 90 meV) and slightly
broadening compared with that of pure ZnO nanorods. The
realization of band gap engineering in Zn1ÀxMgxO nanorods and
film enables good complementary ZnO 1D nanostructure and
opens up enormous opportunities for nanoscale photonics,
electronics and medicines.
[attachment=60080]
ABSTRACT
Well-aligned Zn1ÀxMgxO nanorods and film with Mg-content x from 0 to 0.051 have been successfully
synthesized by metal organic chemical vapor deposition (MOCVD) without any catalysts. The
characterization results showed that the diameters and lengths of the nanorods were in the range
of 20–80 nm and 330–360 nm, which possessed wurtzite structure with a c-axis growth direction.
As the increase of Mg precursor flows into the growth chamber, the morphology of Zn1ÀxMgxO evolves
from nanorods to a film with scale-like surface and the height of the nanorods and the film was almost
identical, it is suggested that the growth rate along the c-axis was hardly changed while the growth of
̄ 0} of the Zn1ÀxMgxO has been improved. Photoluminescence and
six equivalent facets of the type {1 0 1
Raman spectra show that the products have a good crystal quality with few oxygen vacancies. With the
Mg incorporation, multiple-phonon scattering become weak and broad, and the intensities of all
observed vibrational modes decrease. And the ultraviolet near-band-edge emission shows a clear
blueshift (x=0.051, as much as 90 meV) and slightly broadening compared with that of pure ZnO
nanorods.
Introduction
One-dimensional (1D) nanostructures of semiconductors have
stimulated great interest due to their importance in scientific
research and potential utilization in optical and electronic devices
[1,2]. Among these nanostructures, ZnO nanowires have drawn
considerable interests as building blocks or basic units for the
fabrication of nanosized devices due to a wide and direct
fundamental bandgap energy of 3.37 eV and a large exciton
binding energy (60 meV) with high mechanical and thermal
stability. Two critical challenges in fabricating ZnO laser diodes
are p-type doping [3–5] and band gap engineering in alloy
semiconductors to create barrier layers and quantum wells which
facilitate radiative recombination by carrier confinement.
Zn1ÀxMgxO, which is realized by alloying ZnO with Mg (permitting
the band gap to be tuned from 3.3 to 7.8 eV for wurtzite- and
cubic-structured Zn1ÀxMgxO [6–8])
Summary
In summary, we have prepared well-aligned Zn1ÀxMgxO
nanorods and film with tunable optical properties by MOCVD
without any catalysts by varying the composition of Mg. The mean
diameters and lengths of the nanorods were in the range of
20–80 nm and 330–360 nm. As the increase of Mg precursor flows
into the growth chamber, the morphology of Zn1ÀxMgxO evolves
from nanorods to a film with scale-like surface. PL and Raman
spectra show that the nanorods and film have a good crystal
quality with few oxygen vacancies. And the UV NBE emission
shows a clear blueshift (x=0.051, as much as 90 meV) and slightly
broadening compared with that of pure ZnO nanorods. The
realization of band gap engineering in Zn1ÀxMgxO nanorods and
film enables good complementary ZnO 1D nanostructure and
opens up enormous opportunities for nanoscale photonics,
electronics and medicines.