Electrically pumped continuous-wave III–V quantum dot lasers on silicon

Abstract

Reliable, efficient electrically pumped silicon-based lasers would enable full integration of photonic and electronic circuits, but have previously only been realized by wafer bonding. Here, we demonstrate the first continuous-wave InAs/GaAs quantum-dot lasers directly grown on silicon substrates with a low threshold current density of 62.5 A/cm 2 , a room-temperature output power exceeding 105 mW, lasing operation up to 120 o C, and over 3,100 hours of continuous-wave operating data collected, giving an extrapolated mean time to failure of over 100,158 hours. The realization of highperformance quantum-dot lasers on silicon is due to the achievement of a low density of threading dislocations on the order of 10 5 cm -2 in the III-V epilayers by combining a nucleation layer and dislocation filter layers with in-situ thermal annealing. These results are a major advance towards silicon-based photonics and photonic-electronic integration, and could provide a route towards reliable and cost-effective monolithic integration of III-V devices on silicon.Increased data throughput between silicon processors in modern information processing demands unprecedented bandwidth and low power consumption beyond the capability of conventional copper interconnects. To meet these requirements, silicon photonics has been under intensive study in recent years 1,2 . Despite rapid progress being made in silicon-based light modulation and detection technology and low-cost silicon optoelectronic integrated devices enabled by the mature CMOS technology 3,4 , an efficient reliable electrically pumped laser on a silicon substrate has remained an unrealized scientific challenge 5 . Group IV semiconductors widely used in integrated circuits, e.g. silicon and germanium, are inefficient light-emitting materials due to their indirect bandgap, introducing a major barrier to the development of silicon photonics. Integration of IIIÐV materials on a silicon platform has been one of the most promising techniques for generating coherent light on silicon. IIIÐV semiconductors with superior optical properties, acting as optical gain media, can be either bonded or epitaxially grown on silicon substrates [6][7][8][9][10][11] , with the latter approach being more attractive for large scale, low-cost, and streamlined fabrication. However, until now, material lattice mismatch and incompatible thermal expansion coefficients between IIIÐV materials and silicon substrates have fundamentally limited the monolithic growth of IIIÐV lasers on silicon substrates by introducing high-density threading dislocations (TDs) 12 .Lasers with active regions formed from III-V quantum dots (QDs), nano-size crystals, can not only offer low threshold current density (J th ) but also reduced temperature sensitivity [13][14][15][16][17] . As shown in Figure 1a, within less than 10 years, the performance of QD lasers has surpassed state-of-the-art quantum-well (QW) lasers developed over the last few decades in terms of J th . QD lasers have now been demonstrated with nearly constan...

Epitaxial growth of GaSb and InAs fins on 300 mm Si (001) by aspect ratio trapping

“…structures allows the fabrication of lasers in the telecommunication wavelength range with improved performance and lower cost [34]. QDs form as a consequence of the stress generated by the lattice mismatch between the heteroepitaxial layer and the substrate, leading to 3D islanding.…”

Mid-infrared integrated photonics on silicon: a perspective

“…epitaxial growth of non-Si materials on Si, enables monolithic integration of devices on the Si platform while taking advantage of the superior optoelectronic properties of non-Si semiconductors. At the telecom band, heteroepitaxial growth has culminated in electrically pumped laser sources on Si based on n-doped Ge [116] and InAs/GaAs quantum dots [117]. In the mid-IR, lasing from heteroepitaxially grown structures on Si has also been achieved based on material systems including GaSb, GeSn, and lead salts.…”

1.55 μm room-temperature lasing from subwavelength quantum-dot microdisks directly grown on (001) Si

“…10 Recently, direct epitaxy of III-V lasers on Si has attracted significant attention with the successful use of self-assembled quantum dots (QDs) as active materials. [11][12][13] The distinctive zerodimensional density of states of QDs offers lower threshold current density with improved thermal stability in III-V lasers, 14 and their discrete localization promises greater immunity to defects associated with III-V/Si heteroepitaxy when compared to their conventional quantum-well counterparts. 15 More interestingly, these QDs are capable of bending or pinning the threading dislocations (TDs) because of their large strain field.…”

“…15 More interestingly, these QDs are capable of bending or pinning the threading dislocations (TDs) because of their large strain field. 16,17 Recently, high performance electrically pumped continuous-wave InAs/GaAs QD lasers with an emission wavelength as long as 1315 nm have been directly grown on offcut silicon substrates, 11 yielding a low threshold current density of 62.5 A cm À2 , and an elevated operation temperature up to 120 C. These lasers have shown respectable operating lifetimes over 3100 h. To exploit the 1550 nm telecom wavelength where long-distance communication can benefit from the least attenuation, developing InP-based QD lasers on silicon is necessary. In this work, optically pumped subwavelength InAs/In(Al)GaAs quantum dot microdisk lasers (MDLs) epitaxially grown on CMOS-compatible (001) silicon emitting at 1.55 lm are reported.…”