Ultrafast decay of non‐equilibrium (hot) phonons in GaN‐based 2DEG channels

Abstract

AbstractFast and ultrafast decay of non‐equilibrium longitudinal optical phonons (hot phonons) is discussed on examples of two‐dimensional electron gas (2DEG) channels confined in nominally‐undoped nitride and selectivelydoped arsenide heterostructures subjected to pulsed dc electric power. At a low–moderate power, a nonmonotonous dependence of the hot‐phonon lifetime on the 2DEG density is found. The fastest decay takes place at ∼2.5 × 1012 cm–2 in GaInAs 2DEG channel and at ∼7 × 1012 cm–2 in GaN 2DEG channel. The result is discussed in terms of plasmon–LO‐phonon resonance. The hot‐phonon lifetime decreases when the supplied power is increased if the 2DEG density exceeds the resonance density. The shortest hot‐phonon lifetime of 60 fs is obtained at/above 50 nW/electron for the lattice‐matched AlInN/AlN/GaN 2DEG channel (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)