4D-STEM data for in situ heating of irradiated amorphous GaAs

These datasets were used to study the recrystallization behavior of ion-irradiated amorphous gallium arsenide (GaAs) using in situ four-dimensional scanning transmission electron microscopy (4D-STEM). The GaAs samples were irradiated with 400 keV Ne$^{++}$ ions to a fluence of $2 \times 10^{16}$ ions/cm$^2$, producing a distinct amorphous layer. Following irradiation, top-down recrystallization occurred at ambient temperature, initiating from the surface and progressing partially into the amorphous layer. The resulting structure is amorphous GaAs sandwiched between two layers of crystalline GaAs. The data were collected from a focused ion beam (FIB)–prepared lamella oriented with the [101] crystallographic direction along the electron beam. In situ heating experiments were performed from room temperature (25 °C) to 400 °C in 50 °C increments using a MEMS-based Protochips heating holder. At each temperature, diffraction datasets were collected sequentially from two distinct regions on the same lamella, region 1 (provided) followed by region 2 (not provided here). Each 4D-STEM acquisition took approximately 12 minutes, introducing both a temperature and time component to the datasets. The data for region 1 are provided here. All datasets were collected on an FEI Titan operated at 300 kV in microprobe mode with a camera length of 770 mm and a convergence semi-angle of 0.76 mrad. The probe step size was 5 nm, resulting in partial overlap between adjacent probe positions. File Types .dm4 (Gatan DigitalMicrograph) files are provided with the raw 4D-STEM data for each region and temperature step. Each dataset corresponds to one acquisition at a defined temperature and region on the lamella. File names state the experimental region (region 1, in this case) and the temperature at which they were collected. Summary of Datasets GaAs irradiated with 400 keV Ne$^{++}$ to $2 \times 10^{16}$ ions/cm² [101]-oriented FIB lamella Temperature range: 25 °C – 400 °C (50 °C increments) Step size: 5 nm Real space pixel size: 5 nm Convergence semi-angle: 0.76 mrad Camera length: 770 mm k-space pixel size: 0.23 mrad Acceleration voltage: 300 kV Los Alamos National Laboratory LA-UR-25-25818. Contact: [e-mail]