The recent progress on Raman scattering in GaN single crystals and GaN/AlN heterostructures is reviewed. Anti-Stokes Raman scattering is used to determine electron-phonon scattering time and decay time constant for longitudinal-optical phonons. In a typical high electron mobility transistor based on GaN/AlN heterostructures, strong resonances are reached for the first-order and second-order Raman scattering processes. Therefore, both Stokes and anti-Stokes Raman intensities are dramatically enhanced. The feasibility for laser cooling of a nitride structure is studied. A further optimization will enable us to reach the threshold for laser cooling. Raman scattering have potential applications in up-conversion lasers and laser cooling of nitride ultrafast electronic and optoelectronic devices.
© 2013 Chinese Optics Letters
Yujie J. Ding and Jacob B. Khurgin, "Resonant Raman scattering in GaN single crystals and GaN-based heterostructures: feasibility for laser cooling," Chin. Opt. Lett. 11, 011901- (2013)