Limits...
Structural and optical properties of germanium nanostructures on Si(100) and embedded in high-k oxides.

Ray SK, Das S, Singha RK, Manna S, Dhar A - Nanoscale Res Lett (2011)

Bottom Line: The structural and optical properties of Ge quantum dots (QDs) grown on Si(001) for mid-infrared photodetector and Ge nanocrystals embedded in oxide matrices for floating gate memory devices are presented.The temperature- and bias-dependent photocurrent spectra of a capped Si/SiGe/Si(001) QDs infrared photodetector device are presented.The properties of Ge nanocrystals of different size and density embedded in high-k matrices grown using radio frequency magnetron sputtering have been studied.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics and Meteorology, Indian Institute of Technology Kharagpur 721302, India. physkr@phy.iitkgp.ernet.in.

ABSTRACT
The structural and optical properties of Ge quantum dots (QDs) grown on Si(001) for mid-infrared photodetector and Ge nanocrystals embedded in oxide matrices for floating gate memory devices are presented. The infrared photoluminescence (PL) signal from Ge islands has been studied at a low temperature. The temperature- and bias-dependent photocurrent spectra of a capped Si/SiGe/Si(001) QDs infrared photodetector device are presented. The properties of Ge nanocrystals of different size and density embedded in high-k matrices grown using radio frequency magnetron sputtering have been studied. Transmission electron micrographs have revealed the formation of isolated spherical Ge nanocrystals in high-k oxide matrix of sizes ranging from 4 to 18 nm. Embedded nanocrystals in high band gap oxides have been found to act as discrete trapping sites for exchanging charge carriers with the conduction channel by direct tunneling that is desired for applications in floating gate memory devices.

No MeSH data available.


Related in: MedlinePlus

The mid-IR photocurrent spectra of capped Ge/Si QDs at different temperatures. The inset curve shows the photocurrent at room temperature under different reverse bias conditions.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211282&req=5

Figure 4: The mid-IR photocurrent spectra of capped Ge/Si QDs at different temperatures. The inset curve shows the photocurrent at room temperature under different reverse bias conditions.

Mentions: Low temperature PC response was measured using a closed cycle cryostat with KBr window. The mid-IR (180-220 meV) PC response of the grown Ge QDs in the temperature range 100-300 K is shown in Figure 4 at zero applied bias. The mid-IR peak at 195 meV is redshifted with increasing temperature up to 175 K. Although the maximum PC response is observed at 175 Ka shoulder peak at (205 meV) is evolved with increasing temperature, which exhibits a redshift up to 175 K. At room temperature these two peaks merge to yield a broader response. The curves in the inset of Figure 4 show the mid-IR PC response at room temperature under different -ve bias voltages. The peak intensity increases with applied -ve bias and saturates at -0.6 V. The PC saturates when no further holes can be pumped out from the confined energy states with increasing bias. The redshift arising in PC on increasing the temperature up to 175 K is not due to Stark effect, since no peak shift is observed by applying external electrical field in both bias polarities at low and room temperatures. The observed redshift and peak PC response can be explained by the excitonic electric field localized at the interface developed at low Ge nanocrystals embedded in high-k matrices.


Structural and optical properties of germanium nanostructures on Si(100) and embedded in high-k oxides.

Ray SK, Das S, Singha RK, Manna S, Dhar A - Nanoscale Res Lett (2011)

The mid-IR photocurrent spectra of capped Ge/Si QDs at different temperatures. The inset curve shows the photocurrent at room temperature under different reverse bias conditions.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211282&req=5

Figure 4: The mid-IR photocurrent spectra of capped Ge/Si QDs at different temperatures. The inset curve shows the photocurrent at room temperature under different reverse bias conditions.
Mentions: Low temperature PC response was measured using a closed cycle cryostat with KBr window. The mid-IR (180-220 meV) PC response of the grown Ge QDs in the temperature range 100-300 K is shown in Figure 4 at zero applied bias. The mid-IR peak at 195 meV is redshifted with increasing temperature up to 175 K. Although the maximum PC response is observed at 175 Ka shoulder peak at (205 meV) is evolved with increasing temperature, which exhibits a redshift up to 175 K. At room temperature these two peaks merge to yield a broader response. The curves in the inset of Figure 4 show the mid-IR PC response at room temperature under different -ve bias voltages. The peak intensity increases with applied -ve bias and saturates at -0.6 V. The PC saturates when no further holes can be pumped out from the confined energy states with increasing bias. The redshift arising in PC on increasing the temperature up to 175 K is not due to Stark effect, since no peak shift is observed by applying external electrical field in both bias polarities at low and room temperatures. The observed redshift and peak PC response can be explained by the excitonic electric field localized at the interface developed at low Ge nanocrystals embedded in high-k matrices.

Bottom Line: The structural and optical properties of Ge quantum dots (QDs) grown on Si(001) for mid-infrared photodetector and Ge nanocrystals embedded in oxide matrices for floating gate memory devices are presented.The temperature- and bias-dependent photocurrent spectra of a capped Si/SiGe/Si(001) QDs infrared photodetector device are presented.The properties of Ge nanocrystals of different size and density embedded in high-k matrices grown using radio frequency magnetron sputtering have been studied.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics and Meteorology, Indian Institute of Technology Kharagpur 721302, India. physkr@phy.iitkgp.ernet.in.

ABSTRACT
The structural and optical properties of Ge quantum dots (QDs) grown on Si(001) for mid-infrared photodetector and Ge nanocrystals embedded in oxide matrices for floating gate memory devices are presented. The infrared photoluminescence (PL) signal from Ge islands has been studied at a low temperature. The temperature- and bias-dependent photocurrent spectra of a capped Si/SiGe/Si(001) QDs infrared photodetector device are presented. The properties of Ge nanocrystals of different size and density embedded in high-k matrices grown using radio frequency magnetron sputtering have been studied. Transmission electron micrographs have revealed the formation of isolated spherical Ge nanocrystals in high-k oxide matrix of sizes ranging from 4 to 18 nm. Embedded nanocrystals in high band gap oxides have been found to act as discrete trapping sites for exchanging charge carriers with the conduction channel by direct tunneling that is desired for applications in floating gate memory devices.

No MeSH data available.


Related in: MedlinePlus