Optical And Transport Properties Of Devices Utilizing Nanoscale Deep-Centers

Abstract

We demonstrate how nanoscale deep-centers make possible novel devices for THz applications and 1.5um fiber-optic emitters on GaAs. We report the first GaAs light-emitting-diode (LED) emitting at 1.5υm fiber-optic wavelengths from arsenic-antisite deep-levels. This is an enabling technology for 1.5um fiber-optic components latticematched to GaAs ICs. We demonstrate experimental results for significant internal optical power (24mW), efficiency (0.6 percent), and speed (THz) from GaAs deep-level optical emitters. We demonstrate the first GaAs tunnel diodes utilizing arsenic-antisite deep-levels. At room temperature, our measured peak current density (16kA/cm2) is the largest ever in GaAs tunnel diodes. Our devices also show room-temperature peak-to-valley current ratios as high as 22. We ascertain the transport mechanisms which limit the peak and valley currents. Finally, we present the first fully-analytical multi-band model of the deep-center wave function. (e.g., symmetry and admixture of atomic orbitals). This wave function determines the general optical properties (optical selection-rules and transition strengths) of deep-centers in terms of simple materials parameters (bandgap energy, Kane dipole) and angular momenta quantum numbers. This model is applicable in a wide variety of materials, and is in agreement with experiment.