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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.


The I-V curves of the PDs based on ZnO or MgZnO seed layer without metal oxide coating measured at dark and under 365 nm UV light.
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Figure 4: The I-V curves of the PDs based on ZnO or MgZnO seed layer without metal oxide coating measured at dark and under 365 nm UV light.

Mentions: In order to investigate the effect of the seed layer on the performance of PDs, ZnO NRs are prepared with two kinds of seed layers (MgZnO and ZnO seed layers). Herein, high pure ZnO is chosen for the matching of energy band with that of ZnO NRs. MgZnO is chosen due to its low carrier density and large band gap (about 4.0 eV). Figure 4 shows the I-V curves of the PDs without oxide coating and annealed at 300°C, which demonstrates the electron transport characteristics of PDs with different seed layers at dark and under 365-nm UV light, respectively. From the curves, it can be seen that the contacts between Pt and ZnO NRs are good Schottky contacts. At dark, the PD with MgZnO seed layer has lower dark current than that with ZnO seed layer, which may be attributed to the lower carrier density of MgZnO film. Under 365-nm UV light, the current of the PD with MgZnO seed layer is higher than that of the PD with ZnO seed layer at forward bias. The ratios of photocurrent to dark current calculated for the PDs with MgZnO and ZnO seed layer at 5 V are 3.9 and 8.2, respectively.


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)

The I-V curves of the PDs based on ZnO or MgZnO seed layer without metal oxide coating measured at dark and under 365 nm UV light.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: The I-V curves of the PDs based on ZnO or MgZnO seed layer without metal oxide coating measured at dark and under 365 nm UV light.
Mentions: In order to investigate the effect of the seed layer on the performance of PDs, ZnO NRs are prepared with two kinds of seed layers (MgZnO and ZnO seed layers). Herein, high pure ZnO is chosen for the matching of energy band with that of ZnO NRs. MgZnO is chosen due to its low carrier density and large band gap (about 4.0 eV). Figure 4 shows the I-V curves of the PDs without oxide coating and annealed at 300°C, which demonstrates the electron transport characteristics of PDs with different seed layers at dark and under 365-nm UV light, respectively. From the curves, it can be seen that the contacts between Pt and ZnO NRs are good Schottky contacts. At dark, the PD with MgZnO seed layer has lower dark current than that with ZnO seed layer, which may be attributed to the lower carrier density of MgZnO film. Under 365-nm UV light, the current of the PD with MgZnO seed layer is higher than that of the PD with ZnO seed layer at forward bias. The ratios of photocurrent to dark current calculated for the PDs with MgZnO and ZnO seed layer at 5 V are 3.9 and 8.2, respectively.

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.