Raman tensor of AlN bulk single crystal

Abstract

The angle dependence of optical phonon modes of an AlN bulk single crystal from the m-plane (1100) and c-plane (0001) surfaces, respectively, is investigated by polarized Raman spectroscopy in a backscattering configuration at room temperature. Corresponding Raman selection rules are derived according to measured scattering geometries to illustrate the angle dependence. The angle-dependent intensities of phonon modes are discussed and compared to theoretical scattering intensities, yielding the Raman tensor elements of A 1 TO, E 2 2 , E 1 TO, and A 1 LO phonon modes and the relative phase difference between the two complex elements of A 1 TO. Furthermore, the Raman tensor of wurtzite AlN is compared with that of wurtzite ZnO reported in previous work, revealing the intrinsic differences of lattice vibration dynamics between AlN and ZnO.

RF loss mechanisms in GaN‐based high‐electron‐mobility‐transistor on silicon: Role of an inversion channel at the AlN/Si interface

“…The Raman mode of Si substrate is used for calibration. As mentioned above, the tensile stress in AlN can be identified as being proportional to the red‐shift of E 2 mode, in comparison with AlN bulk crystal (at 657 cm −1 ). As can be seen, the E 2 mode of 200‐nm AlN/Si at 649.9 cm −1 is lower than the E 2 mode of 100‐nm AlN/Si at 651.3 cm −1 , which indicates a higher biaxial stress in the thicker AlN buffer/Si.…”

“…Raman spectra of 100‐nm AlN/Si (red) and of 200‐nm AlN/Si (black) (b). The dashed line shows the E 2 mode of AlN bulk single crystal .…”

Experimental observation of high intrinsic thermal conductivity of AlN

“…19 As shown in Figure 1(a), the AlN studied in this work has a wurtzite crystal structure and four atoms in one unit cell. Figure 1 20 The other three peaks are from the sapphire substrates. 21 All the Raman peaks are clean and sharp.…”

Anisotropic temperature‐dependence of optical phonons in layered PbI2

“…Phonon properties are closely related to the Joule heating produced by high-current density, which greatly harms the performance of optoelectronic devices. [11,12] Additionally, electron-phonon interactions are important determinants for thermal conductivity and heat dissipation in the optoelectronic devices. [13] Therefore, for the development of PbI 2 -based optoelectronic devices, it is essential to study its phonon properties.…”