1：Experimental Design and Method Selection:

Physical vapour condensation method was used to fabricate ZnO nanorods. The morphology was investigated using scanning electron microscope (SEM), and X-ray diffraction (XRD) was used to analyze the structure. DC conductivity was measured using the four-probe method over a temperature range of 297-4.2K, with data analyzed using Mott's variable range hopping models (3D VRH for 297-120K and 2D VRH for 120-4.2K).

2：2K, with data analyzed using Mott's variable range hopping models (3D VRH for 297-120K and 2D VRH for 120-2K). Sample Selection and Data Sources:

2. Sample Selection and Data Sources: ZnO powder purchased from Sigma Aldrich Inc. was used to deposit nanorods on glass substrates cooled with liquid nitrogen (LN2).

3：2). List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment includes a vacuum chamber with rotatory and diffusion pumps, molybdenum boat, SEM (Carl Zeiss), X-ray diffractometer (Rigaku model Ultima IV), wire-bonding machine, electrometer (Keithley, model 617), and copper-constantan thermocouple. Materials include ZnO powder, argon gas, and glass substrates.

4：Experimental Procedures and Operational Workflow:

ZnO powder was placed in a molybdenum boat inside a vacuum chamber at 10^-6 Torr. Argon gas was purged to maintain 5 Torr pressure. The boat was heated to evaporate ZnO, depositing nanorods on LN2-cooled glass substrates. SEM and XRD were used for characterization. For conductivity, the sample was wire-bonded, and four-probe measurements were conducted with a constant 1.5V DC voltage, using an electrometer to measure current and a thermocouple for temperature.

5：5V DC voltage, using an electrometer to measure current and a thermocouple for temperature. Data Analysis Methods:

5. Data Analysis Methods: DC conductivity data were fitted to Mott's 3D VRH model (lnσ√T vs T^{-1/4} plot) for 297-120K and 2D VRH model (lnσ vs T^{-1/3} plot) for 120-4.2K to estimate parameters like density of states and hopping distance.