Surprisingly, when Raman maps were created with a higher laser intensity (bottom row in Figure ), a clear trend emerges as a function of potential. More specifically, we observe the presence of dark spots (i.e. no InAs signal), the density of which increases with potential. A typical Raman spectrum at the dark spot is shown in Figure , where a broad band appears and is typically found in amorphous As and As2O3. The light-induced heating and decomposition of InAs into amorphous and oxide compounds has been previously reported in the literature. This phenomenon particularly emerges in nanostructured materials, where enhanced light absorption and less efficient heat transport may occur. Thus, the progressive decomposition of InAs with deposition potential is a first indication of decreased crystal size at high voltages and it is further discussed in the next section.