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Ultraviolet photodetectors based on ZnO nanorods-seed layer effect and metal oxide modifying layer effect.

Zhou H, Fang G, Liu N, Zhao X - Nanoscale Res Lett (2011)

Bottom Line: In this paper, we discussed the effect of metal oxide modifying layer on the performance of UV PDs pre- and post-deposition annealing at 300°C, respectively.For Schottky barrier UV PDs with different seed layers, the MgZnO seed layer-PDs without metal oxide coating showed bigger responsivity and larger detectivity (Dλ*) than those of PDs with ZnO seed layer, and the reason was illustrated through energy band theory and the electron transport mechanism.Also the ratio of D254* to D546* was calculated above 8 × 102 for all PDs, which demonstrated that our PDs showed high selectivity for detecting UV light with less influence of light with long wavelength.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electronic Science and Technology and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China. gjfang@whu.edu.cn.

ABSTRACT
Pt/ZnO nanorod (NR) and Pt/modified ZnO NR Schottky barrier ultraviolet (UV) photodetectors (PDs) were prepared with different seed layers and metal oxide modifying layer materials. In this paper, we discussed the effect of metal oxide modifying layer on the performance of UV PDs pre- and post-deposition annealing at 300°C, respectively. For Schottky barrier UV PDs with different seed layers, the MgZnO seed layer-PDs without metal oxide coating showed bigger responsivity and larger detectivity (Dλ*) than those of PDs with ZnO seed layer, and the reason was illustrated through energy band theory and the electron transport mechanism. Also the ratio of D254* to D546* was calculated above 8 × 102 for all PDs, which demonstrated that our PDs showed high selectivity for detecting UV light with less influence of light with long wavelength.

No MeSH data available.


A schematic diagram of PD.
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Figure 1: A schematic diagram of PD.

Mentions: The glass substrates were initially cleaned with acetone in an ultrasonic bath, rinsed with deionized water, and then blown dry with dry N2. Then, a 120-nm ZnO seed layer was deposited by radio frequency-reactive magnetron sputtering at 100°C. Then, ZnO NRs were grown on ZnO-coated glass substrate by hydrothermal method. The details of the hydrothermal conditions for obtaining ZnO NRs have already been reported elsewhere. In brief, the nutrient solution was an aqueous solution of a 0.05 M zinc nitrate hexahydrate (Zn(NO3)2 · 6H2O) and methenamine (C6H12N4). The reaction was kept at 100°C for 2 h, and then, the ZnO NRs flat film was obtained. Then, to investigate the effect of metal oxide-modified layer on the performance of UV PDs, MgZnO, MgO, and Al-doped ZnO were deposited on ZnO NRs at 100°C by a simple mask plate with radio frequency-reactive magnetron sputtering followed by deposition of 100-nm Pt. The thickness of the metal oxide layer was about 50 nm. Finally, for comparison, a few samples were annealed in air at the temperature of 300°C for 2 h. To investigate the effect of seed layer on the performance of UV PDs, MgZnO seed layer-PDs are prepared without coating oxides, and the experimental conditions were the same as has been mentioned above. A schematic structure of PD with the sample size of 1 × 1 cm2 is shown in the inset of Figure 1, and the photon window area is 1 × 4 mm2. The morphology was observed by Sirion field emission scanning electron microscopy (Philips XL30). The photosensitivity was performed using 66984 Xe Arc source (300 W Oriel) and Oriel Cornerstone TM 260 1/4 m Monochromator. The sample was under illumination directly (parallel with the NRs), and the optical power of light was measured by a UV-enhanced Si detector. All the I-V characteristics were measured using a Keithley 4200 electrometer.


Ultraviolet photodetectors based on ZnO nanorods-seed layer effect and metal oxide modifying layer effect.

Zhou H, Fang G, Liu N, Zhao X - Nanoscale Res Lett (2011)

A schematic diagram of PD.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211197&req=5

Figure 1: A schematic diagram of PD.
Mentions: The glass substrates were initially cleaned with acetone in an ultrasonic bath, rinsed with deionized water, and then blown dry with dry N2. Then, a 120-nm ZnO seed layer was deposited by radio frequency-reactive magnetron sputtering at 100°C. Then, ZnO NRs were grown on ZnO-coated glass substrate by hydrothermal method. The details of the hydrothermal conditions for obtaining ZnO NRs have already been reported elsewhere. In brief, the nutrient solution was an aqueous solution of a 0.05 M zinc nitrate hexahydrate (Zn(NO3)2 · 6H2O) and methenamine (C6H12N4). The reaction was kept at 100°C for 2 h, and then, the ZnO NRs flat film was obtained. Then, to investigate the effect of metal oxide-modified layer on the performance of UV PDs, MgZnO, MgO, and Al-doped ZnO were deposited on ZnO NRs at 100°C by a simple mask plate with radio frequency-reactive magnetron sputtering followed by deposition of 100-nm Pt. The thickness of the metal oxide layer was about 50 nm. Finally, for comparison, a few samples were annealed in air at the temperature of 300°C for 2 h. To investigate the effect of seed layer on the performance of UV PDs, MgZnO seed layer-PDs are prepared without coating oxides, and the experimental conditions were the same as has been mentioned above. A schematic structure of PD with the sample size of 1 × 1 cm2 is shown in the inset of Figure 1, and the photon window area is 1 × 4 mm2. The morphology was observed by Sirion field emission scanning electron microscopy (Philips XL30). The photosensitivity was performed using 66984 Xe Arc source (300 W Oriel) and Oriel Cornerstone TM 260 1/4 m Monochromator. The sample was under illumination directly (parallel with the NRs), and the optical power of light was measured by a UV-enhanced Si detector. All the I-V characteristics were measured using a Keithley 4200 electrometer.

Bottom Line: In this paper, we discussed the effect of metal oxide modifying layer on the performance of UV PDs pre- and post-deposition annealing at 300°C, respectively.For Schottky barrier UV PDs with different seed layers, the MgZnO seed layer-PDs without metal oxide coating showed bigger responsivity and larger detectivity (Dλ*) than those of PDs with ZnO seed layer, and the reason was illustrated through energy band theory and the electron transport mechanism.Also the ratio of D254* to D546* was calculated above 8 × 102 for all PDs, which demonstrated that our PDs showed high selectivity for detecting UV light with less influence of light with long wavelength.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electronic Science and Technology and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China. gjfang@whu.edu.cn.

ABSTRACT
Pt/ZnO nanorod (NR) and Pt/modified ZnO NR Schottky barrier ultraviolet (UV) photodetectors (PDs) were prepared with different seed layers and metal oxide modifying layer materials. In this paper, we discussed the effect of metal oxide modifying layer on the performance of UV PDs pre- and post-deposition annealing at 300°C, respectively. For Schottky barrier UV PDs with different seed layers, the MgZnO seed layer-PDs without metal oxide coating showed bigger responsivity and larger detectivity (Dλ*) than those of PDs with ZnO seed layer, and the reason was illustrated through energy band theory and the electron transport mechanism. Also the ratio of D254* to D546* was calculated above 8 × 102 for all PDs, which demonstrated that our PDs showed high selectivity for detecting UV light with less influence of light with long wavelength.

No MeSH data available.