The remote epitaxy of GaN epilayers on GaN/sapphire templates was studied by using different graphene interlayer types. Monolayer, bilayer, double-stack of monolayer, and triple-stack of monolayer graphenes were transferred onto GaN/sapphire templates using a wet transfer technique. The quality of the graphene interlayers was examined by Raman spectroscopy. The impact of the interlayer type on GaN nucleation was analyzed by scanning electron microscopy. The graphene interface and structural quality of GaN epilayers were studied by transmission electron microscopy and X-ray diffraction, respectively. The influence of the graphene interlayer type is discussed in terms of the differences between remote epitaxy and van der Waals epitaxy. The successful exfoliation of GaN membrane is demonstrated.

Adsorption of decapeptide neuromedin B (NMB) on copper electrode has been investigated by in situ surface-enhanced Raman scattering (SERS) spectroelectrochemistry in the temperature interval from 12 to 72 °C at −0.600 and −1.000 V potentials. It was found that intensities of peptide bands decrease at temperatures above 30 °C with higher decrease slope at −1.000 V. Frequency of F12 mode (1004 cm⁻¹) of non-surface-interactive phenylalanine residue was found to be insensitive to temperature variation at both studied electrode potentials, while frequency–temperature curves for surface-interactive groups (Amide-III, methylene) were found to be controlled by the potential. In particular, opposite frequency–temperature trends were detected for Amide-III (Am-III) mode indicating decrease in H-bonding interaction strength of amide CO and N–H groups above 38 °C for −0.600 V, and increase in H-bonding interaction strength between 12 and 72 °C for −1.000 V. Anomalous Am-III temperature-dependence of the frequency at −1.000 V was explained by temperature-induced transformation of a disordered secondary structure to a helix-like conformation. The potential-difference spectrum revealed interaction of methylene groups with Cu surface at sufficiently negative potential values because of the appearance of a soft C–H stretching band near 2825 cm⁻¹ and a broad band near 2904 cm⁻¹ assigned to vibration of a distal C–H bond of the surface-confined methylene group. Consequently, a rapid decrease in frequency of CH₂-stretching band with temperature was observed at −1.000 V, while no essential frequency changes were detected for this mode at −0.600 V. The results show that electrode potential controls the temperature-dependence of the frequency for vibrations associated with surface-interactive molecular groups.