Towards Electrically Pumped Nanolasers for Terabit Communication

This thesis deals with modeling, design, fabrication and characterization of vertically electrically pumped photonic crystal light-emitting devices. For this purpose a new material platform of III-V semiconductors on silicon has been developed. The devices fabricated on this platform can be used as optical interconnects, where compatibility with Complementary Metal Oxide Semiconductor (CMOS) technology is required.

The first part of this work is dedicated to modeling and simulations of electrically pumped photonic crystal nanolasers with diverse material configurations and different concepts for electrical injection. The analysis of the models is conducted with focus on laser performances, energy efficiency, and thermal properties.

The second part of this thesis deals with design, fabrication and characterization of vertically electrically pumped photonic crystal light-emitting devices. The devices consist of a double heterostructure Photonic Crystal (PhC) membrane with line-defect waveguide for the optical configuration and a pillar under the membrane as a path for vertical electrical injection.

The fabricated devices have been tested under electrical injection and photonic crystal light-emitting diodes (LEDs) have been demonstrated. Furthermore the characterization of the devices under optical injection resulted in lasing emission. The main result of this work is the realization of vertically electrically pumped photonic crystal light-emitting devices on a new material platform.

This result has been achieved through a long and complicated cleanroom fabrication process. The processing includes the development of a mutual SiO2-benzocyclobutene (BCB) planarization with approximately the same dry etch rate for SiO2 and BCB and double-side processing through adhesive BCB bonding to silicon.

The use of chip-mark alignment had to be employed for the second electron-beam lithography of the PhC pattern, in order to compensate for the discovered random sample distortion after the bonding step.