The strong thermal impact in the hot zone during laser treatment, which is the upper half of the device, yields the highly graphitized transducer layer as concluded from HRTEM, electron diffraction, 4D-STEM, EELS and Raman microscopy (Figure -H, Figure , Figure ). Independent of the reaction atmosphere the surface Raman spectra show common features of a turbostratic graphitic material, i.e. the presence of pronounced D-, G-, and Dʹ-bands, indicating a high degree of graphitization. Notably, the LPO2-Ade38090/Glu30010 sensor, processed in oxygen atmosphere, shows a significantly higher degree of graphitization as only negligible contributions of sp -and disorder-related D4 and D3 bands at 1200 and 1460 cm -1 , respectively, and a lower defect-attributed D-band are observed. In more detail, 4D-STEM revealed a strong interplay of local morphology and crystal structure within the transducer layer. The systematic alignment of the surface-near graphite basal planes parallel to the local pore surfaces, indicated in individual HRTEM micrographs (e.g., Figure ), is depicted on a global scale in Figure and Figure (cf. Figure , explanation in Figure ). The representative region of the transducer layer yielded more than 50% of the graphitic material (with (001) excited for evaluation) within only ± 20° misalignment (inset in Figure ).