Fig. 2: Crystallographic and morphological characterization of the sensor device.
From: Voltage-controlled NiO/ZnO p–n heterojunction diode: a new approach towards selective VOC sensing
a XRD spectrum of NiO/ZnO heterojunction showing distinct peaks of NiO (marked with red ligands) and ZnO (marked with blue ligands), supporting coexistence of the two oxides. Low intense peaks of NiO depict the relative position of NiO w.r.t. ZnO surface b FESEM image (sectional view) showing the heterojunction formation. Clear junction between NiO (flakes) and ZnO (hierarchical nanostructures) on top can be observed c FESEM image (top view) showing formation of ZnO hierarchical nanostructures on NiO flakes. The dark areas depict NiO d EDAX spectrum of the NiO/ZnO heterojunction showing top layer ZnO (intense peak of Zn) and bottom layer NiO (comparatively less intense peak of Ni)
