Lateral charge carrier transport properties of B-10 enriched hexagonal boron nitride epilayers*

Hexagonal boron nitride (h-BN) has emerged as a promising candidate for many technologically significant applications due to its unique physical properties. However, h-BN is one of the least studied members of the III-nitride materials system and many important fundamental properties including room temperature carrier mobility, lifetime and surface recombination velocity remain unexplored. We report Time-of-Flight (TOF) probed room temperature lateral carrier drift mobilities (µ) and lifetimes (τ) for both electrons and holes in highly resistive, wide bandgap h-BN epilayers. Photoconductive type detectors were fabricated from freestanding B-10 enriched h-BN material. We obtained values of µ_e ~ 34 cm²/Vs for electrons and µ_h ~ 36 cm²/Vs for holes and carrier lifetimes on the order of 10 μs. Surface recombination velocity (S) was then calculated by combining the µ from TOF with the ratio of S to µ (S/µ) extracted directly from the bias voltage dependence of photocurrent. These results represent a valuable contribution to the understanding of the electrical transport properties of h-BN.