Abstract:Phosphorus-doped ZnO nanorods were successfully prepared by hydrothermal method using ammonium dihydrogen phosphate as the dopant source. The effects of different Zn sources, zinc nitrate concentration, reaction duration, ammonium dihydrogen phosphate concentration, and annealing temperature on the morphologies and phosphorus content of ZnO nanorods were investigated. The doping mechanism of phosphorus-doped ZnO nanorods has been discussed. Detailed photoluminescence studies of phosphorus-doped ZnO revealed ch… Show more
“…Though all the other parameters kept constant or slowed down to increase or decrease except the doping concentration, the length and diameter of the nanorods were still found to be increased, which indicates the successful incorporation of phosphorus into the ZnO nanorods [12, 25]. The chemical reactions responsible for the growth of ZnO and the doping of phosphorus into the ZnO crystals can be understood from the following equations [16]:Fig. 2Top (left) and cross-sectional (right) SEM images of ZnO nanorods corresponding to NH 4 H 2 (PO 4 ) 2 M ratios 0% ( a ), 0.05% ( b ), 0.1% ( c ), 0.2% ( d ), 0.5% ( e ), and 1.0% ( f ), respectively.…”
Section: Resultsmentioning
confidence: 99%
“…In addition, the ammonium dihydrogen phosphate reacts with the already existing hydroxyl ions in the beaker and forms phosphate ions along with ammonium ions and a water molecule. We note here that these phosphate ions react with the zinc ions to form zinc phosphate (Zn 3 (PO 4 ) 2 ) precipitation, which is detrimental to the incorporation of phosphorus into ZnO nanorods [16]. However, the zinc nitrate being the strong acid and strong alkaline salt, it has a potential to minimize the possibility of zinc phosphate precipitation and hence can increase the probability of successful incorporation of phosphorus into ZnO nanorods [16].…”
Section: Resultsmentioning
confidence: 99%
“…We note here that these phosphate ions react with the zinc ions to form zinc phosphate (Zn 3 (PO 4 ) 2 ) precipitation, which is detrimental to the incorporation of phosphorus into ZnO nanorods [16]. However, the zinc nitrate being the strong acid and strong alkaline salt, it has a potential to minimize the possibility of zinc phosphate precipitation and hence can increase the probability of successful incorporation of phosphorus into ZnO nanorods [16]. The phosphorus doping in ZnO nanorods is known to induce p-type conductivity from their inherent n-type conductivity [7, 27, 28], which will further validate the doping of phosphorus atoms.…”
Section: Resultsmentioning
confidence: 99%
“…However, we cannot clearly say how much is the solubility limit of phosphorus when it comes to growing p-type ZnO with NH 4 H 2 (PO 4 ) 2 via hydrothermal process, but we believe the solubility limit should be somewhere around 7.8 × 10 15 cm −2 . It is noteworthy that the carrier concentration can be increased by post-thermal annealing process as mentioned in [16]. However, the annealing process changes not only carrier concentrations but also their diameter, length, and density of the nanorods unexpectedly [16].…”
Section: Resultsmentioning
confidence: 99%
“…Therefore, the phosphorus was considered to be one of the most reliable and stable ones for inducing the p-type conductivity in ZnO among the aforementioned dopants. Moreover, the phosphorus in ZnO nanostructures was found to trigger the oxygen vacancy-related photoluminescence (PL) emission in the visible region [8, 16]. Though there have been several reports on the PL emission study of ZnO nanostructures [17–22], a systematic study that can cover the luminescence in the three different and important regimes of the electromagnetic spectra including ultraviolet (UV), visible, and near-infrared (NIR) regimes along with their electrical and structural properties is quite scarce.…”
The phosphorus-doped ZnO nanorods were prepared using hydrothermal process, whose structural modifications as a function of doping concentration were investigated using X-ray diffraction. The dopant concentration-dependent enhancement in length and diameter of the nanorods had established the phosphorus doping in ZnO nanorods. The gradual transformation in the type of conductivity as observed from the variation of carrier concentration and Hall coefficient had further confirmed the phosphorus doping. The modification of carrier concentration in the ZnO nanorods due to phosphorus doping was understood on the basis of the amphoteric nature of the phosphorus. The ZnO nanorods in the absence of phosphorus showed the photoluminescence (PL) in the range of the ultraviolet (UV) and visible regimes. The UV emission, i.e. near-band-edge emission of ZnO, was found to be red-shifted after the doping of phosphorus, which was attributed to donor-acceptor pair formation. The observed emissions in the visible regime were due to the deep level emissions that were aroused from various defects in ZnO. The Al-doped ZnO seed layer was found to be responsible for the observed near-infrared (NIR) emission. The PL emission in UV and visible regimes can cover a wide range of applications from biological to optoelectronic devices.
“…Though all the other parameters kept constant or slowed down to increase or decrease except the doping concentration, the length and diameter of the nanorods were still found to be increased, which indicates the successful incorporation of phosphorus into the ZnO nanorods [12, 25]. The chemical reactions responsible for the growth of ZnO and the doping of phosphorus into the ZnO crystals can be understood from the following equations [16]:Fig. 2Top (left) and cross-sectional (right) SEM images of ZnO nanorods corresponding to NH 4 H 2 (PO 4 ) 2 M ratios 0% ( a ), 0.05% ( b ), 0.1% ( c ), 0.2% ( d ), 0.5% ( e ), and 1.0% ( f ), respectively.…”
Section: Resultsmentioning
confidence: 99%
“…In addition, the ammonium dihydrogen phosphate reacts with the already existing hydroxyl ions in the beaker and forms phosphate ions along with ammonium ions and a water molecule. We note here that these phosphate ions react with the zinc ions to form zinc phosphate (Zn 3 (PO 4 ) 2 ) precipitation, which is detrimental to the incorporation of phosphorus into ZnO nanorods [16]. However, the zinc nitrate being the strong acid and strong alkaline salt, it has a potential to minimize the possibility of zinc phosphate precipitation and hence can increase the probability of successful incorporation of phosphorus into ZnO nanorods [16].…”
Section: Resultsmentioning
confidence: 99%
“…We note here that these phosphate ions react with the zinc ions to form zinc phosphate (Zn 3 (PO 4 ) 2 ) precipitation, which is detrimental to the incorporation of phosphorus into ZnO nanorods [16]. However, the zinc nitrate being the strong acid and strong alkaline salt, it has a potential to minimize the possibility of zinc phosphate precipitation and hence can increase the probability of successful incorporation of phosphorus into ZnO nanorods [16]. The phosphorus doping in ZnO nanorods is known to induce p-type conductivity from their inherent n-type conductivity [7, 27, 28], which will further validate the doping of phosphorus atoms.…”
Section: Resultsmentioning
confidence: 99%
“…However, we cannot clearly say how much is the solubility limit of phosphorus when it comes to growing p-type ZnO with NH 4 H 2 (PO 4 ) 2 via hydrothermal process, but we believe the solubility limit should be somewhere around 7.8 × 10 15 cm −2 . It is noteworthy that the carrier concentration can be increased by post-thermal annealing process as mentioned in [16]. However, the annealing process changes not only carrier concentrations but also their diameter, length, and density of the nanorods unexpectedly [16].…”
Section: Resultsmentioning
confidence: 99%
“…Therefore, the phosphorus was considered to be one of the most reliable and stable ones for inducing the p-type conductivity in ZnO among the aforementioned dopants. Moreover, the phosphorus in ZnO nanostructures was found to trigger the oxygen vacancy-related photoluminescence (PL) emission in the visible region [8, 16]. Though there have been several reports on the PL emission study of ZnO nanostructures [17–22], a systematic study that can cover the luminescence in the three different and important regimes of the electromagnetic spectra including ultraviolet (UV), visible, and near-infrared (NIR) regimes along with their electrical and structural properties is quite scarce.…”
The phosphorus-doped ZnO nanorods were prepared using hydrothermal process, whose structural modifications as a function of doping concentration were investigated using X-ray diffraction. The dopant concentration-dependent enhancement in length and diameter of the nanorods had established the phosphorus doping in ZnO nanorods. The gradual transformation in the type of conductivity as observed from the variation of carrier concentration and Hall coefficient had further confirmed the phosphorus doping. The modification of carrier concentration in the ZnO nanorods due to phosphorus doping was understood on the basis of the amphoteric nature of the phosphorus. The ZnO nanorods in the absence of phosphorus showed the photoluminescence (PL) in the range of the ultraviolet (UV) and visible regimes. The UV emission, i.e. near-band-edge emission of ZnO, was found to be red-shifted after the doping of phosphorus, which was attributed to donor-acceptor pair formation. The observed emissions in the visible regime were due to the deep level emissions that were aroused from various defects in ZnO. The Al-doped ZnO seed layer was found to be responsible for the observed near-infrared (NIR) emission. The PL emission in UV and visible regimes can cover a wide range of applications from biological to optoelectronic devices.
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