Novel deep centers for high-performance optical materials

Progress to a Gallium-Arsenide Deep-Center Laser

“…Our previous work [6,7] showed that, as the injection increases, the hole quasi-Fermi-level within the first L${}_P$ of the deep-center layer drops from near midgap to near E${}_{\text{V}}$, as indicated in Figure 13a–c. This is manifest in the measured spectra, Figure 13d, as a shift of the optical-emission from half the bandgap energy (1.6 μ m) to shorter wavelengths (1.0 μ m) near the bandgap.…”

“…In sharp contrast to the PL, the EL spectral shape changes significantly with injection, as shown [7] in Figure 5b (and Figure 8a). Figure 5b shows the PL spectrum (dashed-dotted line), on top of which is superimposed several EL spectra (solid and dashed lines), for sample C. The EL spectra have been normalized so that the EL peaks lie on top of the PL spectrum.…”

“…Figure 3a shows [7] room temperature PL from GaAs deep-centers and from InGaAs. The excitation in Figure 3a,b was a 10 mW HeNe laser.…”

“…It is also well known [7,8,11,13,17,18] that the donor-V${}_{\text{Ga}}$ complex shows a Franck-Condon spectral shift of absorption away from luminescence, because V${}_{\text{Ga}}$ is highly coupled to the lattice. (Arrows a and b in Figure 6a show luminescence and absorption at the same energies.…”

“…Figure 6c shows that [7], at wavelengths (1-1.7 μ m) of bright PL from the GaAs deep-centers, the material is nearly transparent even at zero injection. The measured transmission through the GaAs deep-centers in Figure 6c indicates an absorption loss of less than 3.6 cm${}^{-1}$ at 1.6 μ m wavelengths.…”