Spectroscopic Evidence for Exceptional Thermal Contribution to Electron Beam-Induced Fragmentation

Abstract

While electron beam induced fragmentation (EBIF) has been reported to result in the formation of nanocrystals of various compositions, the physical forces driving this phenomenon are still poorly understood. We report EBIF to be a much more general phenomenon than previously appreciated, operative across a wide variety of metals, semiconductors and insulators. In addition, we leverage the temperature dependent bandgap of several semiconductors to quantify -using in situ cathodoluminescence spectroscopy -the thermal contribution to EBIF, and find extreme temperature rises upwards of 1000K.

Nucleation and growth of Ni0 nanoparticles and thin films by TEM electron irradiation

“…Other materials reported with EBIF phenomenon are Pb [6], SnO 2 [7], GeTe [8], BiNi [9,10]. Recently, Caldwell et al [11] have investigated the generality of EBIF of a wide variety of materials and showed that EBIF occurs by a mechanism in which the materials go through a thermally induced phase transition, like it was proposed initially [5].…”

“…In this study, the reduction temperature of NiO was around 350 • C, however, the temperature reduction of NiO changed between 350 and 600 • C when it was supported on ZrO 2 -CeO 2 . From this point of view [4,11,21], the electron irradiation can increase the local temperature of a sample by hundreds of Celsius degrees, even up to 1000 • C or more in bulk irradiation, depending on material [21]. This means that, the local temperature that the NiO can achieve during the electron irradiation should easily reduce it, in conjunction with appropriate conditions within the microscope column.…”

“…Bi 0 nanoparticles were not reported to become ejected from agglomerates. Caldwell [11] and Pyrz [10], suggested a mechanism for the formation of nanocrystals referred as EBIF. In the case, the formation of nanoparticles take place for a few seconds, in our case, although the first nanoparticles appear in the first few seconds the growth of them continue until the formation of a thin film.…”

Temperature dependence of secondary electron emission: A new route to nanoscale temperature measurement using scanning electron microscopy

“…A few experimental efforts to measure temperature using electron microscopy have been reported. Electron energy loss spectroscopy (EELS) and cathodoluminescence spectroscopy (CLS) have been used to measure the temperature of metals 6 and semiconducting materials, 7 respectively. Transmission electron microscope (TEM) diffraction patterns of Si and Ge have shown a temperature response coefficient β of around 10 −3 K −1 due to thermal diffuse scattering.…”

Employing Cathodoluminescence for Nanothermometry and Thermal Transport Measurements in Semiconductor Nanowires

“…At high beam currents, the beam acts like a nearly delta function heat source while simultaneously probing the temperature. CL has seldom been used for thermometry, , and it has not, to our knowledge, been used for nanoscale thermal imaging or to study thermal conductivity. In our method of CL thermometry, the spatial resolution is limited primarily by the electron beam cascade size in the material, which can be in the range of about 1–200 nm depending on the electron energy, and also by the electron probe size and the minority carrier diffusion length .…”