Rebecca Schaevitz

With germanium showing significant promise in the design of electroabsorption modulators for full complementary metal oxide semiconductor integration, we present a simple electroabsorption calculator for Ge/SiGe quantum wells. To simulate the quantum-confined Stark effect electroabsorption profile, this simple quantum well electroabsorption calculator (SQWEAC) uses the tunneling resonance method, 2-D Sommerfeld enhancement, the variational method and an indirect absorption model. SQWEAC… Show more

With germanium showing significant promise in the design of electroabsorption modulators for full complementary metal oxide semiconductor integration, we present a simple electroabsorption calculator for Ge/SiGe quantum wells. To simulate the quantum-confined Stark effect electroabsorption profile, this simple quantum well electroabsorption calculator (SQWEAC) uses the tunneling resonance method, 2-D Sommerfeld enhancement, the variational method and an indirect absorption model. SQWEAC simulations are compared with experimental data to validate the model before presenting optoelectronic modulator designs for the important communication bands of 1310 nm and 1550 nm. These designs predict operation with very low energy per bit ( <= 30×fJ/bit). Show less

We present a simple quantum well electroabsorption calculator (SQWEAC) for the germanium material system to facilitate optoelectronic modulator design. We show SQWEAC is valid for a range of quantum well sizes and growth conditions.

Germanium has become a promising material for creating CMOS-compatible optoelectronic devices, such as modulators and detectors employing the Franz-Keldysh effect (FKE) or the quantum-confined Stark effect (QCSE), which meet strict energy and density requirements for future interconnects. To improve Ge-based modulator design, it is important to understand the contributions to the insertion loss (IL). With indirect absorption being the primary component of IL, we have experimentally determined… Show more

Germanium has become a promising material for creating CMOS-compatible optoelectronic devices, such as modulators and detectors employing the Franz-Keldysh effect (FKE) or the quantum-confined Stark effect (QCSE), which meet strict energy and density requirements for future interconnects. To improve Ge-based modulator design, it is important to understand the contributions to the insertion loss (IL). With indirect absorption being the primary component of IL, we have experimentally determined the strength of this loss and compared it with theoretical models. For the first time, we have used the more sensitive photocurrent measurements for determining the effective absorption coefficient in our Ge/SiGe quantum well material employing QCSE. This measurement technique enables measurement of the absorption coefficient over four orders of magnitude. We find good agreement between our thin Ge quantum wells and the bulk material parameters and theoretical models. Similar to bulk Ge, we find that the 27.7 meV LA phonon is dominant in these quantum confined structures and that the electroabsorption profile can be predicted using the model presented by Frova, Phys. Rev., 145 (1966). Show less

Germanium (Ge) and silicon-germanium (Si-Ge) have the potential to integrate optics with Si IC technology. The quantum-confined Stark effect, a strong electroabsorption mechanism often observed in III-V quantum wells (QWs), has been demonstrated in Si-Ge/Ge QWs, allowing optoelectronic modulators in such group IV materials. Here, based on photocurrent electroabsorption experiments on different samples and fitting of the resulting allowed and nominally forbidden transitions, we propose more… Show more

Germanium (Ge) and silicon-germanium (Si-Ge) have the potential to integrate optics with Si IC technology. The quantum-confined Stark effect, a strong electroabsorption mechanism often observed in III-V quantum wells (QWs), has been demonstrated in Si-Ge/Ge QWs, allowing optoelectronic modulators in such group IV materials. Here, based on photocurrent electroabsorption experiments on different samples and fitting of the resulting allowed and nominally forbidden transitions, we propose more accurate values for key parameters such as effective masses and band offsets that are required for device design. Tunneling resonance modeling including conduction band nonparabolicity was used to fit the results with good consistency between the experiments and the fitted transitions. Show less