Limits...
Observation and tunability of room temperature photoluminescence of GaAs/GaInAs core-multiple-quantum-well shell nanowire structure grown on Si (100) by molecular beam epitaxy.

Park KW, Park CY, Ravindran S, Jang JS, Jo YR, Kim BJ, Lee YT - Nanoscale Res Lett (2014)

Bottom Line: The GaAs/GaInAs core-MQW shell NW surrounded by AlGaAs also shows an enhanced PL intensity due to the improved carrier confinement owing to the presence of an AlGaAs clad layer.The inclined growth of the GaAs NWs produces a core-MQW shell structure having a different PL peak position than that of planar QWs.The PL emission by MQW shell and the ability to tune the PL peak position by varying the shell width make such core-shell NWs highly attractive for realizing next generation ultrasmall light sources and other optoelectronics devices. 81.07.Gf; 81.15.Hi; 78.55.Cr.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Information and Communications, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712, Republic of Korea.

ABSTRACT

Unlabelled: We report the observation of room temperature photoluminescence (PL) emission from GaAs/GaInAs core-multiple-quantum-well (MQW) shell nanowires (NWs) surrounded by AlGaAs grown by molecular beam epitaxy (MBE) using a self-catalyzed technique. PL spectra of the sample show two PL peaks, originating from the GaAs core NWs and the GaInAs MQW shells. The PL peak from the shell structure red-shifts with increasing well width, and the peak position can be tuned by adjusting the width of the MQW shell. The GaAs/GaInAs core-MQW shell NW surrounded by AlGaAs also shows an enhanced PL intensity due to the improved carrier confinement owing to the presence of an AlGaAs clad layer. The inclined growth of the GaAs NWs produces a core-MQW shell structure having a different PL peak position than that of planar QWs. The PL emission by MQW shell and the ability to tune the PL peak position by varying the shell width make such core-shell NWs highly attractive for realizing next generation ultrasmall light sources and other optoelectronics devices.

Pacs: 81.07.Gf; 81.15.Hi; 78.55.Cr.

No MeSH data available.


Normalized PL spectra of GaAs/GaInAs MQW shell on GaAs NW with different quantum-well widths. (a) 8.0 nm, (b) 11 nm, and (c) 16 nm. The red line represents the PL spectra of the planar GaInAs MQWs grown on GaAs substrate. Inset in (a) shows the increase of PL intensity of GaAs NW due to the presence of MQW shells. PL peak corresponding to GaInAs shell shifted to lower energy with the increase of GaInAs shell width.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4257527&req=5

Figure 6: Normalized PL spectra of GaAs/GaInAs MQW shell on GaAs NW with different quantum-well widths. (a) 8.0 nm, (b) 11 nm, and (c) 16 nm. The red line represents the PL spectra of the planar GaInAs MQWs grown on GaAs substrate. Inset in (a) shows the increase of PL intensity of GaAs NW due to the presence of MQW shells. PL peak corresponding to GaInAs shell shifted to lower energy with the increase of GaInAs shell width.

Mentions: Figure 6a,b,c shows the normalized PL spectra (normalized with respect to PL of GaAs core) of GaAs/GaInAs core-MQW shell NWs surrounded by AlGaAs structures with three different well widths measured at room temperature. The composition of 8-nm-thick planar GaInAs MQWs grown on GaAs substrate remained the same as that of the 8-nm-thick MQW shell NW grown on GaAs core. To the best of our knowledge, this is the first observation of room temperature PL spectra from a MBE grown GaAs/GaInAs core-MQW shell NW surrounded by AlGaAs clads. Unlike the previous report [21], the presence of the AlGaAs clad layer helps the carriers to be tightly confined in the quantum wells [34] preventing carriers escaping from the wells and enabling room temperature PL measurements. The PL spectra shown in Figure 6 are comprised of two peaks; one around 1.42 eV which corresponds to the PL emission from the GaAs NW core and the other situated at an energy lower than 1.42 eV, which corresponds to the PL emission from the GaInAs shell. The PL peak energy of the grown GaAs NW core is slightly lower than that of pure ZB GaAs NW due to the fact that the grown NWs are polytypic (i.e., a mixture of WZ and ZB structures) [35]. The inset of Figure 6a shows the comparison of the PL intensity from a bare GaAs NW and of core-MQW shell NW structure which has an 8-nm-thick GaInAs shell. The PL spectrum of the core-MQW shell NW is predominated by the emission from the GaAs core with the peak around 1.42 eV, and the PL spectrum of the bare GaAs NW is also found at around 1.42 eV. However, as seen from the figure, the PL peak intensity of GaAs NW is greatly enhanced owing to the presence of the shell structure acting as a passivation layer which suppresses non-radiative recombination centers [35].


Observation and tunability of room temperature photoluminescence of GaAs/GaInAs core-multiple-quantum-well shell nanowire structure grown on Si (100) by molecular beam epitaxy.

Park KW, Park CY, Ravindran S, Jang JS, Jo YR, Kim BJ, Lee YT - Nanoscale Res Lett (2014)

Normalized PL spectra of GaAs/GaInAs MQW shell on GaAs NW with different quantum-well widths. (a) 8.0 nm, (b) 11 nm, and (c) 16 nm. The red line represents the PL spectra of the planar GaInAs MQWs grown on GaAs substrate. Inset in (a) shows the increase of PL intensity of GaAs NW due to the presence of MQW shells. PL peak corresponding to GaInAs shell shifted to lower energy with the increase of GaInAs shell width.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4257527&req=5

Figure 6: Normalized PL spectra of GaAs/GaInAs MQW shell on GaAs NW with different quantum-well widths. (a) 8.0 nm, (b) 11 nm, and (c) 16 nm. The red line represents the PL spectra of the planar GaInAs MQWs grown on GaAs substrate. Inset in (a) shows the increase of PL intensity of GaAs NW due to the presence of MQW shells. PL peak corresponding to GaInAs shell shifted to lower energy with the increase of GaInAs shell width.
Mentions: Figure 6a,b,c shows the normalized PL spectra (normalized with respect to PL of GaAs core) of GaAs/GaInAs core-MQW shell NWs surrounded by AlGaAs structures with three different well widths measured at room temperature. The composition of 8-nm-thick planar GaInAs MQWs grown on GaAs substrate remained the same as that of the 8-nm-thick MQW shell NW grown on GaAs core. To the best of our knowledge, this is the first observation of room temperature PL spectra from a MBE grown GaAs/GaInAs core-MQW shell NW surrounded by AlGaAs clads. Unlike the previous report [21], the presence of the AlGaAs clad layer helps the carriers to be tightly confined in the quantum wells [34] preventing carriers escaping from the wells and enabling room temperature PL measurements. The PL spectra shown in Figure 6 are comprised of two peaks; one around 1.42 eV which corresponds to the PL emission from the GaAs NW core and the other situated at an energy lower than 1.42 eV, which corresponds to the PL emission from the GaInAs shell. The PL peak energy of the grown GaAs NW core is slightly lower than that of pure ZB GaAs NW due to the fact that the grown NWs are polytypic (i.e., a mixture of WZ and ZB structures) [35]. The inset of Figure 6a shows the comparison of the PL intensity from a bare GaAs NW and of core-MQW shell NW structure which has an 8-nm-thick GaInAs shell. The PL spectrum of the core-MQW shell NW is predominated by the emission from the GaAs core with the peak around 1.42 eV, and the PL spectrum of the bare GaAs NW is also found at around 1.42 eV. However, as seen from the figure, the PL peak intensity of GaAs NW is greatly enhanced owing to the presence of the shell structure acting as a passivation layer which suppresses non-radiative recombination centers [35].

Bottom Line: The GaAs/GaInAs core-MQW shell NW surrounded by AlGaAs also shows an enhanced PL intensity due to the improved carrier confinement owing to the presence of an AlGaAs clad layer.The inclined growth of the GaAs NWs produces a core-MQW shell structure having a different PL peak position than that of planar QWs.The PL emission by MQW shell and the ability to tune the PL peak position by varying the shell width make such core-shell NWs highly attractive for realizing next generation ultrasmall light sources and other optoelectronics devices. 81.07.Gf; 81.15.Hi; 78.55.Cr.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Information and Communications, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712, Republic of Korea.

ABSTRACT

Unlabelled: We report the observation of room temperature photoluminescence (PL) emission from GaAs/GaInAs core-multiple-quantum-well (MQW) shell nanowires (NWs) surrounded by AlGaAs grown by molecular beam epitaxy (MBE) using a self-catalyzed technique. PL spectra of the sample show two PL peaks, originating from the GaAs core NWs and the GaInAs MQW shells. The PL peak from the shell structure red-shifts with increasing well width, and the peak position can be tuned by adjusting the width of the MQW shell. The GaAs/GaInAs core-MQW shell NW surrounded by AlGaAs also shows an enhanced PL intensity due to the improved carrier confinement owing to the presence of an AlGaAs clad layer. The inclined growth of the GaAs NWs produces a core-MQW shell structure having a different PL peak position than that of planar QWs. The PL emission by MQW shell and the ability to tune the PL peak position by varying the shell width make such core-shell NWs highly attractive for realizing next generation ultrasmall light sources and other optoelectronics devices.

Pacs: 81.07.Gf; 81.15.Hi; 78.55.Cr.

No MeSH data available.