[19p-C42-1~15] 15.4 III-V-group nitride crystals

1:15 PM - 1:30 PM JST(4:15 AM - 4:30 AM UTC)English Presentation

[19p-C42-2] Condition of phonon transport augmentation at GaInN/GaN heterointerface

〇(DC)KhaingShwe TheeEi¹, Tatsuya Asaji¹, Bei Ma¹, Daisuke Iida², Mohammed A. Najmi², Kazuhiro Ohkawa², Yoshihiro Ishitani¹ (1.Chiba Univ., 2.KAUST)

Keywords:

Raman scattering,phonon transport,double-laser system

The pump and probe technique in Raman spectroscopy of the E2(high) mode is exploited to uncover the enhancing factor of the phonon transport across Ga_1-xIn_xN/GaN interfaces. Two samples are investigated: one with a uniform x of 0.09 (sample A) and another one with a graded variation in x from 0.17(sample B). The higher-energy branches of the E₂(high) modes of GaInN and GaN films were characterized using a microscopic Raman imaging system with two lasers of 532-nm (signal probing) and 325-nm (heating and signal probing). Figure1(a) shows the decrement of the E₂(high) energy of the GaN template when the two lasers are incident on the same position, revealing that sample B includes regions with higher thermal transport at the heterointerface than sample A. Figure 1 (b) shows DE_E2H of the GaN layer by irradiating the 325-nm laser in the same region. DE_E2H or DT values of the GaN layer in the vicinity of the positions of 1, 2, and 3 are higher than those in the other regions. According to Fig. 1(c), the phonon transport is thought to be high at interfaces comprising materials with closer E₂(high) mode energies.