Optical properties of Si0.8Ge0.2/Si multiple quantum wells

Shim, Kyu–Hwan; Kil, Yeon‐Ho; Lee, H.K.; Shin, Mi Im; Jeong, T. S.; Kang, Suhyun; Choi, Chel‐Jong; Kim, T.S.

doi:10.1016/j.mssp.2011.01.016

Cited by 4 publications

(3 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…room temperature. The spectra show that no Ge-related PL signals are detected at room temperature, but a peak centred at about 1240 nm becomes appreciable if the temperature is lowered down to 100 K, reaching its maximum intensity at 11 K. The peak position corresponds to the literature data dealing with luminescent Ge nanostructures [78][79][80]. Furthermore, it is noticed that the PL emission exhibits a blueshift with a decreasing temperature, which is in agreement with the well-known dependence of the Ge bandgap on temperature.…”

Section: Synthesis and Optical Properties Of Si/ge Nwssupporting

confidence: 64%

Light-emitting silicon nanowires obtained by metal-assisted chemical etching

Irrera

Faro

D’Andrea

et al. 2017

Semicond. Sci. Technol.

View full text Add to dashboard Cite

This review reports on a new process for the synthesis of Si nanowires (NWs), based on the wet etching of Si substrates assisted by a thin metal film. The approach exploits the thicknessdependent morphology of the metal layers to define uncovered nanometric Si regions, which behave as precursor sites for the formation of very dense (up to 1×10 12 NW cm −2 ) arrays of long (up to several μm) and ultrathin (diameter of 5-9 nm) NWs. Intense photoluminescence (PL) peaks, characterized by maxima in the 640-750 nm range and by an external quantum efficiency of 0.5%, are observed when the Si NWs are excited at room temperature. The spectra show a blueshift if the size of the NW is decreased, in agreement with the occurrence of quantum confinement effects. The same etching process can be used to obtain ultrathin Si/Ge NWs from a Si/Ge multi-quantum well. The Si/Ge NWs exhibit-in addition to the Si-related PL peak-a signal at about 1240 nm due to Ge nanostructures. The huge surface area of the Si NW arrays can be exploited for sensing and analytical applications. The dependence of the PL intensity on the chemical composition of the surface indeed suggests interesting perspectives for the detection of gaseous molecules. Moreover, Si NWs decorated with Ag nanoparticles can be effectively employed in the interference-free laser desorption-ionization mass spectrometry of lowmolecular-weight analytes. A device based on conductive Si NWs, showing intense and stable electroluminescence at an excitation voltage as low as 2 V, is also presented. The unique features of the proposed synthesis (the process is cheap, fast, maskless and compatible with Si technology) and the unusual optical properties of the material open the route towards new and unexpected perspectives for semiconductor NWs in photonics.

show abstract

Section: Synthesis and Optical Properties Of Si/ge Nwssupporting

confidence: 64%

Light-emitting silicon nanowires obtained by metal-assisted chemical etching

Irrera

Faro

D’Andrea

et al. 2017

Semicond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…On the other hand, a PL signal appears in the IR region at about 1,240 nm (red squares), as shown in Figure 5b. The peak position is in agreement with literature data concerning light emission from Ge nanostructures [19-21]. It is noteworthy that the emission is enhanced by about a factor of 5 with respect to that one coming from the unetched MQW, shown in the same figure as blue squares, which suggests that stronger quantum confinement effects are operating in the NWs (where Ge regions can be considered as nanodots) with respect to the MQW.…”

Section: Resultssupporting

confidence: 90%

Visible and infrared emission from Si/Ge nanowires synthesized by metal-assisted wet etching

Irrera¹,

Artoni

Fioravanti

et al. 2014

Nanoscale Res Lett

View full text Add to dashboard Cite

Multi-quantum well Si/Ge nanowires (NWs) were realized by combining molecular beam epitaxy deposition and metal-assisted wet etching, which is a low-cost technique for the synthesis of extremely dense (about 1011 cm−2) arrays of NWs with a high and controllable aspect ratio. In particular, we prepared ultrathin Si/Ge NWs having a mean diameter of about 8 nm and lengths spanning from 1.0 to 2.7 μm. NW diameter is compatible with the occurrence of quantum confinement effects and, accordingly, we observed light emission assignable to the presence of Si and Ge nanostructures. We performed a detailed study of the photoluminescence properties of the NWs, with particular attention to the excitation and de-excitation properties as a function of the temperature and of the excitation photon flux, evaluating the excitation cross section and investigating the presence of non-radiative phenomena.PACS61.46.Km; 78.55.-m; 78.67.Lt

show abstract

“…On the other hand, a PL signal appears in the IR region at about 1240 nm, as shown in Figure 4b. The peak position is in agreement with literature data concerning light emission from Ge nanostructures (7)(8). It is noteworthy that the emission is enhanced by about a factor of 5 with respect to that one coming from the unetched MQW, shown in the same figure, which suggests that stronger quantum confinement effects are operating in the NWs (where Ge regions can be considered as nanodots) with respect to the MQW.…”

Section: Silicon Nanowiressupporting

confidence: 91%