Jonathan T. Bessette

An electrically pumped germanium laser

Electrically pumped lasing from Germanium-on-Silicon pnn heterojunction diode structures is demonstrated. Room temperature multimode laser with 1mW output power is measured. Phosphorous doping in Germanium at a concentration over 4x1019cm-3 is achieved. A Germanium gain spectrum of nearly 200nm is observed.

High active carrier concentration in n-type, thin film Ge using delta-doping

We demonstrate CVD in situ doping of Ge by utilizing phosphorus delta-doping for the creation of a high dopant diffusion source. Multiple monolayer delta doping creates source phosphorous concentrations above 1 × 1020cm−3, and uniform activated dopant concentrations above 4 × 1019cm−3 in a 600-800nm thick Ge layer after in-diffusion. By controlling dopant out-diffusion, near-complete incorporation of phosphorus diffusion source is shown.

An electrically pumped Ge-on-Si laser

We present the first CMOS compatible, electrically pumped Fabry-Perot Ge laser with larger than 1mW output power and a gain spectrum width of nearly 200nm in the range from 1520nm to 1700nm.

High phosphorous doped germanium: Dopant diffusion and modeling

The in situ n-type doping of Ge thin films epitaxial grown on Si substrates is limited to 1 × 1019 cm−3 by the phosphorous out-diffusion during growth at 600 °C. By studying the phosphorous diffusion in Ge with different background doping, we find that the diffusion coefficient is extrinsic and is enhanced 100 times in Ge doped at 1 × 1019 cm−3 compared to intrinsic diffusivity. To achieve higher phosphorous concentration, delta-doped layers are used as a dopant source for phosphorous in-diffusion. We show that the doping level is a result of the competition between in-diffusion and dopant loss. The high diffusivity at high n-type carrier concentration leads to a uniform distribution of phosphorous in Ge with the concentration above 3 × 1019 cm−3.

Optical characterization of Ge-on-Si laser gain media

Tensile strained Ge films with P concentrations as high as 3.4 × 10¹⁹ cm⁻³ are grown using UHVCVD. Photoluminescence measurements reveal significant direct band gap narrowing, enhanced photoemission, and optical bleaching.

Germanium laser: A CMOS compatible light emitter

CMOS Ge-on-Si pnn multimode laser diode is demonstrated. Calculated losses suggest a gain above 100cm-1. Observed power of above 1mW is reported.

High n-type doped germanium for electrically pumped Ge laser

We demonstrate an active phosphorous concentration of 4x1019 cm-3 in Ge by delta doping. Dopant enhanced diffusion is observed and modeled. Photoluminescence (PL) and electroluminescence (EL) confirm the high doping level with stronger emission.

Electroluminescence of highly doped Ge pnn diodes for Si integrated lasers

Edge-emission electroluminescence from waveguide Ge-on-Si pnn heterojunction diode structures is demonstrated. Selective growth of highly phosphorus doped Ge in oxide trenches shows promise as a design for electrically pumped laser on Si.

Ge laser and on-chip electronic-photonic integration

We present recent progress in monolithic Ge-on-Si lasers for on-chip electronic-photonic integration, with a highlight on electrically-pumped Ge-on-Si lasers with ~1 mW output at λ~1530-1650 nm.

Electrically Pumped Germanium-on-Silicon Laser

Germanium lasing from Ge-on-Si pnn heterojunction diode structures is demonstrated. Selective growth of highly phosphorus doped Ge in oxide trenches shows a design for CMOS compatible laser integration.