Anisotropic three-dimensional weak localization in ultrananocrystalline diamond films with nitrogen inclusions

Abstract

We present a study of the structural and electronic properties of ultra-nanocrystalline diamond films that were modified by adding nitrogen to the gas mixture during chemical vapour deposition growth. Hall bar devices were fabricated from the resulting films to investigate their electrical conduction as a function of both temperature and magnetic field. Through low-temperature magnetoresistance measurements, we present strong evidence that the dominant conduction mechanism in these films can be explained by a combination of 3D weak localization (3DWL) and thermally activated hopping at higher temperatures. An anisotropic 3DWL model is then applied to extract the phase-coherence time as function of temperature, which shows evidence of a power law dependence in good agreement with theory.Electrical measurements were performed on N-UNCD films grown by chemical vapour deposition. These films arXiv:2003.05077v1 [cond-mat.mes-hall]

Size-Dependent Electrical Transport Properties in Conducting Diamond Nanostripes

“…Table 1 lists the reported resistivity ρ, or the conductivity σ (=1/ρ), of N-UNCD films doped with 5% N 2 present in the plasma. Although the resistivity ρ for N-UNCD films varies from 0.009-590.2 Ω cm as reported by different groups [9,[19][20][21][22][23], both 150 nm and 75 nm wide nanostripes have much higher resistivities than these reported values for the thin film counterparts. As shown in Table 1, the resistivity of 75 nm wide nanostripe is about 100 times larger than the reported resistivity of an N-UNCD thin film doped with 5% N 2 in the reactor.…”

A Delicate Balance Between Spin‐Wave Mediated Weak Localization and Electron‐Phonon Scattering in the Design of Zero Temperature Coefficient of Resistivity

“…This mechanism will be broken when a strong disorder is induced, such as the failure of lattice periodicity. The typical consequence is the WL of conduction electrons, [ 21,22 ] which leads to a decrease in resistivity with the increase in temperature, particularly at low‐temperatures. In a system with both WL of conduction electrons and common e‐p scattering electrons, the temperature‐dependent resistivity originating from WL and e‐p scattering may counteract each other, resulting in a non‐temperature interference in resistance.…”