Thermal phonon modulation of III-nitride semiconductors under strong electric fields

Self-heating effects in high-power III-nitride semiconductor electronics and optoelectronic devices limit their practical applications, while phonon modulation can be used to alleviate heat dissipation problems. In this paper, we report our efforts to suppress macroscopic polarization fields when applying strong electric fields, which affect the phonon frequency. We investigate alterations in phonon frequencies for two materials, 2H-GaN and 2H-AlN, for various electric field strengths ranging from 0.00 V/& ANGS; to 0.07 V/& ANGS; and 0.00 V/& ANGS; to 0.18 V/& ANGS;, respectively. We also analyze the changes in the macroscopic dielectric tensor and the BORN effective charge tensor. The calculation results reveal that the vibration frequencies of the longitudinal-optical (LO) A1(LO) mode are decreased by approximately 2 cm-1 for 2H-GaN and 3 cm-1 for 2H-AlN. Our simulation results are consistent with the Raman spectroscopy results of Si-doped 2H-GaN specimens illuminated with 325 nm excitation for a variety of carrier concentrations. This study contributes to a better understanding of the factors influencing phonon behavior, thus offering new methods for optimizing the thermal regulation and dissipation patterns of III-nitride semiconductor materials and devices.

Automated summary

In this paper, we investigate the suppression of macroscopic polarization fields and alterations in phonon frequencies under strong electric fields in high-power III-nitride semiconductor devices. The vibration frequencies of the LO A1(LO) mode in 2H-GaN and 2H-AlN decrease by approximately 2 cm-1 and 3 cm-1, respectively. The simulation results are supported by Raman spectroscopy results of Si-doped 2H-GaN specimens. This study provides insights into the factors influencing phonon behavior and offers new methods for optimizing thermal regulation and dissipation in III-nitride semiconductor materials and devices.