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Electrical, structural, and optical properties of sulfurized Sn-doped In2O 3 nanowires.

Zervos M, Mihailescu CN, Giapintzakis J, Othonos A, Travlos A, Luculescu CR - Nanoscale Res Lett (2015)

Bottom Line: We observe the existence of cubic bixbyite In2O3 and hexagonal SnS2 after processing the Sn:In2O3 nanowires to H2S at 300 °C but also cubic bixbyite In2O3, which remains dominant, and the emergence of rhombohedral In2(SO4)3 at 400 °C.The resultant nanowires maintain their metallic-like conductivity, and exhibit photoluminescence at 3.4 eV corresponding to band edge emission from In2O3.In contrast, Sn:In2O3 nanowires grown on glass at 500 °C can be treated under H2S only below 200 °C which is important for the fabrication of Cu2S/Sn:In2O3 core-shell p-n junctions on low-cost transparent substrates such as glass suitable for quantum dot-sensitized solar cells.

View Article: PubMed Central - PubMed

Affiliation: Nanostructured Materials and Devices Laboratory, Department of Mechanical and Manufacturing Engineering, P.O. Box 20537, Nicosia, 1678, Cyprus, zervos@ucy.ac.cy.

ABSTRACT
Sn-doped In2O3 nanowires have been grown on Si via the vapor-liquid-solid mechanism at 800 °C and then exposed to H2S between 300 to 600 °C. We observe the existence of cubic bixbyite In2O3 and hexagonal SnS2 after processing the Sn:In2O3 nanowires to H2S at 300 °C but also cubic bixbyite In2O3, which remains dominant, and the emergence of rhombohedral In2(SO4)3 at 400 °C. The resultant nanowires maintain their metallic-like conductivity, and exhibit photoluminescence at 3.4 eV corresponding to band edge emission from In2O3. In contrast, Sn:In2O3 nanowires grown on glass at 500 °C can be treated under H2S only below 200 °C which is important for the fabrication of Cu2S/Sn:In2O3 core-shell p-n junctions on low-cost transparent substrates such as glass suitable for quantum dot-sensitized solar cells.

No MeSH data available.


Ultrafast transient spectroscopy of ITO. Right inset shows the ultrafast transient of the SnS2:In2O3 NWs obtained from the ITO NWs under H2S at 300 °C for 60 min; left inset shows the steady state absorption-transmission spectra of the ITO and SnS2:In2O3 NWs
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Fig4: Ultrafast transient spectroscopy of ITO. Right inset shows the ultrafast transient of the SnS2:In2O3 NWs obtained from the ITO NWs under H2S at 300 °C for 60 min; left inset shows the steady state absorption-transmission spectra of the ITO and SnS2:In2O3 NWs

Mentions: The Sn-doped In2O3 NWs exposed to H2S at 300 °C exhibited PL at λ = 340 nm or 3.4 eV as shown in Fig. 3 corresponding to band edge emission from In2O3. The emergence of band edge emission at ≈3.4 eV is still accompanied by the broader PL around 500 nm or 2.5 eV observed in the as-grown Sn-doped In2O3 NWs. The emergence of band edge emission is attributed to a suppression of the surface recombination similar to what has been observed in the case of bulk ZnO [7]. Here, it should be noted that SnS2 is an indirect band gap semiconductor but exhibits defect-related PL around 2.0–2.5 eV as we have shown recently by post growth processing of SnO2 NWs under H2S [20]. In addition, note that InS has an indirect energy gap of 1.9 eV, β-In2S3 is an n-type semiconductor with a direct band gap of 2.1 eV while it has been found that the optical band gap varies from 2.1 eV in pure β-In2S3 to 2.9 eV in β-In2S3-3xO3x when it contains 8.5 at.% of oxygen [13]. Consequently the PL the Sn-doped In2O3 NWs at ≈3.4 eV is related to the cubic bixbyite In2O3 which is dominant after post growth processing under H2S between 300 to 400 °C. For completeness, the steady state transmission through the Sn-doped In2O3 NWs grown on fused silica at 800 °C before and after post growth processing under H2S at 200 °C is shown as an inset in Fig. 4. One may observe a slight reduction in the maximum transmission and a small red shift, but the overall shape has not changed, and the maximum occurs at λ ≈ 1000 nm. This red shift is consistent with ultrafast, differential absorption-transmission spectroscopy measurements, shown in Fig. 4. The differential transmission through the Sn-doped In2O3 NWs grown on fused silica between λ = 550 to 600 nm is positive and decays over a few tens of ps, but we observe a suppression of the λ = 550 nm trace and increase in differential transmission around λ = 650 to 700 nm after post growth processing under H2S as shown by the inset in Fig. 4. This is attributed to the formation of SnS2 on the surface of the Sn-doped In2O3 NWs and is responsible for the red shift observed in the steady state transmission spectrum.Fig. 4


Electrical, structural, and optical properties of sulfurized Sn-doped In2O 3 nanowires.

Zervos M, Mihailescu CN, Giapintzakis J, Othonos A, Travlos A, Luculescu CR - Nanoscale Res Lett (2015)

Ultrafast transient spectroscopy of ITO. Right inset shows the ultrafast transient of the SnS2:In2O3 NWs obtained from the ITO NWs under H2S at 300 °C for 60 min; left inset shows the steady state absorption-transmission spectra of the ITO and SnS2:In2O3 NWs
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4522004&req=5

Fig4: Ultrafast transient spectroscopy of ITO. Right inset shows the ultrafast transient of the SnS2:In2O3 NWs obtained from the ITO NWs under H2S at 300 °C for 60 min; left inset shows the steady state absorption-transmission spectra of the ITO and SnS2:In2O3 NWs
Mentions: The Sn-doped In2O3 NWs exposed to H2S at 300 °C exhibited PL at λ = 340 nm or 3.4 eV as shown in Fig. 3 corresponding to band edge emission from In2O3. The emergence of band edge emission at ≈3.4 eV is still accompanied by the broader PL around 500 nm or 2.5 eV observed in the as-grown Sn-doped In2O3 NWs. The emergence of band edge emission is attributed to a suppression of the surface recombination similar to what has been observed in the case of bulk ZnO [7]. Here, it should be noted that SnS2 is an indirect band gap semiconductor but exhibits defect-related PL around 2.0–2.5 eV as we have shown recently by post growth processing of SnO2 NWs under H2S [20]. In addition, note that InS has an indirect energy gap of 1.9 eV, β-In2S3 is an n-type semiconductor with a direct band gap of 2.1 eV while it has been found that the optical band gap varies from 2.1 eV in pure β-In2S3 to 2.9 eV in β-In2S3-3xO3x when it contains 8.5 at.% of oxygen [13]. Consequently the PL the Sn-doped In2O3 NWs at ≈3.4 eV is related to the cubic bixbyite In2O3 which is dominant after post growth processing under H2S between 300 to 400 °C. For completeness, the steady state transmission through the Sn-doped In2O3 NWs grown on fused silica at 800 °C before and after post growth processing under H2S at 200 °C is shown as an inset in Fig. 4. One may observe a slight reduction in the maximum transmission and a small red shift, but the overall shape has not changed, and the maximum occurs at λ ≈ 1000 nm. This red shift is consistent with ultrafast, differential absorption-transmission spectroscopy measurements, shown in Fig. 4. The differential transmission through the Sn-doped In2O3 NWs grown on fused silica between λ = 550 to 600 nm is positive and decays over a few tens of ps, but we observe a suppression of the λ = 550 nm trace and increase in differential transmission around λ = 650 to 700 nm after post growth processing under H2S as shown by the inset in Fig. 4. This is attributed to the formation of SnS2 on the surface of the Sn-doped In2O3 NWs and is responsible for the red shift observed in the steady state transmission spectrum.Fig. 4

Bottom Line: We observe the existence of cubic bixbyite In2O3 and hexagonal SnS2 after processing the Sn:In2O3 nanowires to H2S at 300 °C but also cubic bixbyite In2O3, which remains dominant, and the emergence of rhombohedral In2(SO4)3 at 400 °C.The resultant nanowires maintain their metallic-like conductivity, and exhibit photoluminescence at 3.4 eV corresponding to band edge emission from In2O3.In contrast, Sn:In2O3 nanowires grown on glass at 500 °C can be treated under H2S only below 200 °C which is important for the fabrication of Cu2S/Sn:In2O3 core-shell p-n junctions on low-cost transparent substrates such as glass suitable for quantum dot-sensitized solar cells.

View Article: PubMed Central - PubMed

Affiliation: Nanostructured Materials and Devices Laboratory, Department of Mechanical and Manufacturing Engineering, P.O. Box 20537, Nicosia, 1678, Cyprus, zervos@ucy.ac.cy.

ABSTRACT
Sn-doped In2O3 nanowires have been grown on Si via the vapor-liquid-solid mechanism at 800 °C and then exposed to H2S between 300 to 600 °C. We observe the existence of cubic bixbyite In2O3 and hexagonal SnS2 after processing the Sn:In2O3 nanowires to H2S at 300 °C but also cubic bixbyite In2O3, which remains dominant, and the emergence of rhombohedral In2(SO4)3 at 400 °C. The resultant nanowires maintain their metallic-like conductivity, and exhibit photoluminescence at 3.4 eV corresponding to band edge emission from In2O3. In contrast, Sn:In2O3 nanowires grown on glass at 500 °C can be treated under H2S only below 200 °C which is important for the fabrication of Cu2S/Sn:In2O3 core-shell p-n junctions on low-cost transparent substrates such as glass suitable for quantum dot-sensitized solar cells.

No MeSH data available.