Beam damage of single semiconductor nanowires during X-ray nanobeam diffraction experiments

Abstract

Nanoprobe X-ray diffraction (nXRD) using focused synchrotron radiation is a powerful technique to study the structural properties of individual semiconductor nanowires. However, when performing the experiment under ambient conditions, the required high X-ray dose and prolonged exposure times can lead to radiation damage. To unveil the origin of radiation damage, a comparison is made of nXRD experiments carried out on individual semiconductor nanowires in their as-grown geometry both under ambient conditions and under He atmosphere at the microfocus station of the P08 beamline at the third-generation source PETRA III. Using an incident X-ray beam energy of 9 keV and photon flux of 1010 s−1, the axial lattice parameter and tilt of individual GaAs/In0.2Ga0.8As/GaAs core–shell nanowires were monitored by continuously recording reciprocal-space maps of the 111 Bragg reflection at a fixed spatial position over several hours. In addition, the emission properties of the (In,Ga)As quantum well, the atomic composition of the exposed nanowires and the nanowire morphology were studied by cathodoluminescence spectroscopy, energy-dispersive X-ray spectroscopy and scanning electron microscopy, respectively, both prior to and after nXRD exposure. Nanowires exposed under ambient conditions show severe optical and morphological damage, which was reduced for nanowires exposed under He atmosphere. The observed damage can be largely attributed to an oxidation process from X-ray-induced ozone reactions in air. Due to the lower heat-transfer coefficient compared with GaAs, this oxide shell limits the heat transfer through the nanowire side facets, which is considered as the main channel of heat dissipation for nanowires in the as-grown geometry.

Accurate experimental characterization of the labile N–Cl bond inN-chloro-N′-(p-fluorophenyl)-benzamidine crystal at 17.5 K

“…In the last two decades, extremely brilliant X-ray sources enabled a revolution in solid state chemistry by putting within the reach of diffraction-based techniques the understanding of complex structures and dynamic phenomena, down to the femtosecond timescale. 1 However, the high photon flux of modern high-brilliance facilities may degrade the sample within hours or even minutes, 2 for example when protein crystals 3 or reactive compounds 4 are studied. The lost information can be retrieved, at least to some extent, by scaling and merging data from different fresh crystals, assuming that several high-quality 5 samples are available.…”

In Situ Monitoring of MBE Growth of a Single Self-Catalyzed GaAs Nanowire by X-ray Diffraction

“…According to ref , highly focused X-ray illumination may induce serous beam damage in nanowires. Based on the estimates of ref , we took special care to ensure that the X-ray doze is tolerable and well below the threshold which may lead to the beam damage even after 1 h of illumination.…”

Impact of Electrical Current on Single GaAs Nanowire Structure

“…To explain the existence of oxide onto the side planes, it was discovered recently that the X‐ray nanobeam causes oxide formation along the surface if the experiment has been performed in air. [ 18 ] Additional material also may come from carbon deposition during SEM. However, oxide formation and carbon deposition onto the side planes cannot explain the finding that the NW cross section deduced from nXRD after electrical impact seems to be larger compared to the as‐grown state (see NW B and NW C).…”

“…Finally, a RSM of the GaAs 111 Bragg reflection was recorded for each individual NW by varying the angle of the incident beam and simultaneously recording 2D detector images of the scattering signal. More details about the procedure to record RSMs can be found in the studies by AlHassan et al, Davtyan et al, and AlHassan et al [16][17][18]…”

“…As shown recently, nXRD becomes destructive if the radiation dose exceeds a certain threshold. [ 18 ] However, the nXRD studies shown in this article have been performed at doses much below this threshold.…”