NANOSCALE INVESTIGATION OF LOCAL ELECTRICAL PROPERTIES AND SCHOTTKY CONTACTS IN ALUMINUM-DOPED ZINC OXIDE THIN FILMS USING CONDUCTIVE ATOMIC FORCE MICROSCOPY

Aluminum-doped zinc oxide (AZO) thin films were deposited on silicon substrates using radio-frequency (RF) reactive magnetron sputtering. Conductive atomic force microscopy (C-AFM) was used to analyze the surface morphology and local electrical properties of the films. The results show a uniform surface morphology with a grain size of 50 to 100 nm and a surface roughness of approximately 8 nm. C-AFM current mapping reveals a non-uniform current distribution, where electrical current is localized on the grain surfaces and absent at the grain boundaries. Local current-voltage (I-V) curve measurements indicate that the conductive tip forms a Schottky contact (a metal-semiconductor barrier with rectifying properties) with the film, with starting voltages varying by location. Fitting the I-V curves yields the specific ideality factors (parameters measuring how closely a diode follows ideal thermionic emission theory) of the local Schottky barriers.