The absorption spectra of gallium nitride crystals doped with erbium ions

We have measured the absorption spectra of Er³⁺ ions introduced by diffusion into bulk GaN crystals grown by vapor phase epitaxy in a chloride system. The wavelength interval of 518–527 nm corresponding to the region of the ⁴ I _15/2→² H _11/2 transition was studied in detail at 293, 77, and 2 K. At 2 K, the spectrum of this transition displays six lines, which correspond to the theoretically possible number of sublevels of the ² H _11/2 state of Er³⁺ ion occurring in a noncubic crystal field. The positions of levels in the ² H _11/2 multiplet correspond to 2.360, 2.361, 2.365, 2.369, 2.379, and 2.386 eV. Both the number and narrow width of lines observed at 2 K indicate that Er³⁺ ions predominantly occupy the same regular position in GaN crystals. Most probably, erbium ions occupy gallium sites in the crystal lattice.     

Shock-wave Processes in the Electric Explosion of Thin-Film Systems on Silicon

Silicon - This study investigates the relationship between thermal shocks on the surface of semiconductor wafers and parameters of thermostimulated mechanical vibrations to develop express methods...