Temperature dependent electrical transport studies of self-aligned ZnO nanorods/Si heterostructures deposited by sputtering

Abstract

Self-aligned ZnO nanorods (NRs) were grown on n-Si(100) substrate by RF sputtering techniques. The NRs are uniformly grown on 2-inch wafer along [0001] direction. Single-crystalline wurtzite structure of ZnO NRs was confirmed by X-ray diffraction. The average diameter, height, and density of NRs are found 48 nm, 750 nm, and 1.26 × 1010 cm−2, respectively. The current-voltages (I-V) characteristics of ZnO NRs/Si heterojunction (HJ) were studied in the temperature range of 120–300 K and it shows a rectifying behavior. Barrier height (ϕB) and ideality factor (η) were estimated from thermionic emission model and found to be highly temperature dependent in nature. Richardson constant (A*) was evaluated using Richardson plot of ln(Io/T2) versus q/kT plot by linear fitting in two temperature range 120–180 K and 210–300 K. Large deviation in Richardson constant from its theoretical value of n-Si indicates the presence of barrier inhomogeneities at HJ. Double Gaussian distribution of barrier height with thermionic equation gives mean barrier heights of 0.55 ± 0.01 eV and 0.86 ± 0.02 eV for two different temperature regions 120–180 K and 210–300 K, respectively. Modified Richardson plot provided two values of Richardson constant for two temperature regions. However, for higher temperature range (210–300 K), the calculated value of Richardson constant ∼123 A cm−2 K−2 was close to the ideal Richardson constant for n-Si.

Temperature-dependent current–voltage characteristics of Pd/ZnO Schottky barrier diodes and the determination of the Richardson constant

“…and searchers [2,17,20,22,23]. The difference in the calculated values of the Richardson constant for different temperature ranges can be attributed to inhomogeneity in the barrier.…”

Role of Oxygen Vacancies in the Electrical Properties of WO3−x Nano/Microrods with Identical Morphology

“…Generally, the characteristic I-V curves of one-dimensional nanomaterials are linear [27,28], rectifying [29][30][31][32], asymmetric [29,33], or symmetric [27,34,35]. For the present devices, normally, the contact of metal electrodes with the WO 3−x crystals would be either a Schottky barrier or an Ohmic contact.…”

Growth and Characterization of Indium Oxide, Zinc Oxide and Cadmium Sulfide Nanowires by Vapor-Liquid-Solid Growth Technique

“…The as-grown ZnO NWs have an average length about 20 µm and a diameter in range of 50 to 200 nm. The average length of as grown ZnO NWs is higher than other methods such as RF sputtering techniques (Ranwa, Kulriya, Dixit, & Kumar, 2014) which used to grow the self-aligned ZnO nanorods. The SEM images of as grown In 2 O 3 NWs are shown in Figure 3 where Figure 3 (a, b and c) are showing the top view, side view and randomly grown In 2 O 3 NWs, respectively.…”