In situmonitoring of Joule heating effects in germanium nanowires by μ-Raman spectroscopy

Abstract

We explored a noninvasive optical method to determine the Joule heating of individual germanium nanowires. Using confocal μ-Raman spectroscopy, variations in the optical phonon frequency, in detail the downshifting of the first-order Stokes Raman band, are correlated to the temperature increase of vapor-liquid-solid grown germanium nanowires under an applied electrical bias. The germanium nanowires were found to handle high threshold current densities of more than 10(6) A cm(-2) before sustaining immediate deterioration. Failure of single crystalline germanium nanowires was directly observed when the applied electric field reached the breakdown point of 1.25 × 10(5) V cm(-1).

Enhanced Field Emission of WS2 Nanotubes

“…Resistive heating of the NTs apex above 250 °C could be the reason for such oxidation . This is possible, considering that heating of different types of semiconducting NWs and NTs from ∼500 to ∼1300 °C had been measured and predicted for similar current densities measured here . However, one has to measure and/or estimate the exact temperature rise to clarify this issue.…”

Strained Ge Light Emitter with Ge on Dual Insulators for Improved Thermal Conduction and Optical Insulation

“…This downshift of Raman spectra can be purely attributed to the temperature rise in Ge. According to Lugstein et al [35], the temperature-shift coefficient for the first-order Stokes Raman band for Ge is 0.02 cm -1 /°C. Using this coefficient, one can plot the temperature variation in Ge as a function of the excitation power, as shown in Fig.…”

A novel strategy to prepare Ge@C/rGO hybrids as high-rate anode materials for lithium ion batteries

“…The Raman spectroscopy of Ge@C/rGO hybrids (as shown in Figure S2, Supporting Information) can confirm the existence of carbon and germanium in the Ge@C/rGO composites. The peak located at 298 cm -1 in Ge@C/rGO composites corresponding to the Ge-Ge phonon vibration [42,43]. The two typical Raman peaks at 1345 and1581 cm -1 can be indexed to the D-band and G-band of carbon, respectively [44,45].…”