Ph.D Thesis

Ph.D StudentZamir Shai
SubjectGallium Nitride Based Surface Emitting LEDs on Silicon
DepartmentDepartment of Electrical and Computer Engineering
Supervisor PROFESSOR EMERITUS Yosef Salzman


Gallium nitride (GaN) based devices, such as blue and green light emitting diodes (LEDs) and violet laser diodes (LDs) are already widespread in many applications. These applications include optical media, operated by violet lasers, all-color outdoor displays, green traffic lights, and lately even domestic and automotive illumination.

The growth of GaN-based devices is commonly performed on expensive sapphire or silicon carbide (SiC) substrates. Silicon (Si) substrates, on the other hand, are widely used for electronic applications, and are less costly of the other substrates. The growth of GaN on Si may enable integration between the optoelectronic GaN-based devices and the well established Si electronics.

The aim of this work was to study some of the aspects concerning surface emitter (SE) devices (LEDs and LDs) on Si substrate. The work was based on metal-organic vapor phase epitaxy (MOVPE) growth and fabrication of LEDs and distributed Bragg reflectors (DBRs), required for SE devices, their characterization, and study.

The current study discusses some of the fabrication issues, as well as some interesting physical phenomena. The fabrication issues concern material quality, thermal cracking of GaN on Si, novel growth methods and device realization.  The physical phenomena which are presented, regard the emission color of LEDs as a function of barrier doping, driving current/voltage, and thickness of active layer.