Gallium-arsenide deep-level materials for THz and 1.5μm fiber-optic applications

We demonstrate novel materials utilizing semiconductor deep centers for THz applications and 1.5μm fiber-optic emitters on GaAs. We achieve the first [J.L. Pan, J.E. McManis, T. Osadchy, L. Grober, J.M. Woodall, P.J. Kindlmann, Nat. Mater. 2 (2003) 375] light-emitting diode (LED) in the material GaAs emitting at 1.5μm fiber-optic wavelengths from arsenic-antisite deep levels. This technology enables 1.5μm fiber-optic components lattice matched to GaAs ICs. We experimentally demonstrate significant internal optical power (24mW), efficiency (almost 1%), and available speed (THz) from GaAs deep-level optical emitters. We also achieve the first tunnel diodes explicitly making use of deep-levels in low-temperature-grown (LTG) GaAs. At room temperature, we demonstrate the largest peak current density (16kA/cm2) ever in a GaAs tunnel diode. Our devices also show room-temperature peak-to-valley current ratios greater than 20. We determine the transport mechanisms which limit the peak and valley currents. Finally, we present the first fully analytical eight-band model [J.L. Pan, Opt. Exp. 9 (2001) 796; J.L. Pan, J. Appl. Phys. 92 (2002) 5991] of the deep-center wave function (e.g., symmetry and admixture of atomic orbitals). Our model determines the general optical properties of deep-centers (optical selection-rules and transition strengths) in terms of simple materials properties (band gap energy, Kane dipole, deep-level position) and angular momenta quantum numbers. Thus, our model is applicable in a wide variety of materials, and is in agreement with experiment