Search

In this work, we have developed photoconductor devices based on Al0.39In0.61N layers grown on sapphire by reactive radio-frequency magnetron sputtering. The fabricated devices show a sublinear dependence of the photocurrent as a function of the incident optical power. The above-the-band-gap responsivity reaches 7 W/A for an irradiance of 10 W/m2 (405 nm wavelength). The response decreases smoothly for below-the-bandgap excitation, dropping by more than an order of magnitude at 633 nm. The devices present persistent photoconductivity effects associated to carrier trapping at grain boundaries. [ABSTRACT FROM AUTHOR]

We present an overview of the recently developed III-nitride-based optical waveguides for application in ultrafast signal processing at telecom wavelengths. We focus on different active and passive optical devices for further implementation within all-optical integrated circuits. Optical waveguides based on GaN/AlN quantum dots have been demonstrated to act as saturable absorbers requiring ∼3 pJ of input pulse energy to reach +3 dB transmittance contrast for TM-polarized light. On the contrary, sputtered-InN-based devices show −3 dB transmittance contrast associated to two-photon absorption for input pulse energies of ∼1 pJ, making them suitable to act as highly-efficient reverse saturable absorbers. Finally, the passive optical nature of waveguides based on sputtered AlN at 1.55 μm makes them suitable for further connections between different III-nitride-based active devices. [ABSTRACT FROM AUTHOR]