III-V Quantum Dot Lasers Epitaxially Grown on Si

Abstract

Monolithic integration of semiconductor lasers on silicon platform is the ultimate solution for creating complex optoelectronic circuits, which is the key to chip-to-chip and system-to-system communications. The direct epitaxial integration of III-V semiconductor materials on Si or Ge is one of the most promising approaches for the fabrication of electrically pumped light sources on a Si platform, promising low-cost, high-yield and large-scale deployment of silicon photonics [1], [2]. However, monolithic integration technique faces significant challenges because of the large material dissimilarity between III-V and Group IV materials, such as lattice mismatch, thermal expansion coefficient differences, and polar versus nonpolar surfaces [2], [3]. These differences tend to produce various types of defects, such as, antiphase boundaries (APBs), threading dislocations (TDs), and microcracks, which all generate nonradiative recombination centers and dramatically undermine the promise of III-V materials. Recently, quantum dots (QDs) structure is becoming widely used in active layer in semiconductor lasers due to their advantages of low threshold current density and temperature insensitive operation [4], [5]. Also, QD structures have attracted increasing attention for the monolithic III-V/Si integration due to their enhanced tolerance to defects and special capability of filtering the APBs and threading dislocations [6], [7]. In this paper, we review our recent progress made in the direct growth of III-V QD lasers on Si substrates