Monolithic integration of III-V semiconductor devices on Silicon (Si) has long been of great interest in photonic integrated circuits (PICs), as well as traditional integrated circuits (ICs), since it provides enormous potential benefits, including versatile functionality, low-cost, large-area production, and dense integration. However, the material dissimilarity between III-V and Si, such as lattice constant, coefficient of thermal expansion, and polarity, introduces a high density of various defects during the growth of III-V on Si. In order to tackle these issues, a variety of growth techniques have been developed so far, leading to the demonstration of high-quality III-V materials and optoelectronic devices monolithically grown on various Si-based platform. In this paper, the recent advances in the heteroepitaxial growth of III-V on Si substrates, particularly GaAs and InP, are discussed. After introducing the fundamental and technical challenges for III-V-on-Si heteroepitaxy, we discuss recent approaches for resolving growth issues and future direction towards monolithic integration of III-V on Si platform.

High-performance III-V quantum-dot lasers monolithically grown on Si substrates have been demonstrated as a promising solution to realise Si-based laser sources with very low threshold current density, high output power and long lifetime, even with relatively high density of defects due to the material dissimilarities between III-Vs and Si. On the other hand, although conventional III-V quantum-well lasers grown on Si have been demonstrated after great efforts worldwide for more than 40 years, their practicality is still a great challenge because of their very high threshold current density and very short lifetime. However, the physical mechanisms behind the superior performance of silicon-based III-V quantum-dot lasers remain unclear. In this paper, we directly compare the performance of a quantum-well and a quantum-dot laser monolithically grown on on-axis Si (001) substrates, both experimentally and theoretically, under the impact of the same density of threading dislocations. A quantum-dot laser grown on a Si substrate with a high operating temperature (105 °C) has been demonstrated with a low threshold current density of 173 A/cm $^2$ and a high single facet output power >100 mW at room temperature, while there is no lasing operation for the quantum-well device at room temperature even at high injection levels. By using a rate equation travelling-wave model, the quantum-dot laser's superior performance compared with its quantum well-based counterpart on Si is theoretically explained in terms of the unique properties of quantum dots, i.e., efficient carrier capture and high thermal energy barriers preventing the carriers from migrating into defect states.

Ultra-compact III-V nanolasers monolithically integrated on Si with ultra-low energy consumption and small modal volume have been emerged as one of the most promising candidates to achieve Si on-chip light sources. However, the significant material dissimilarities between III-V and Si fundamentally limit the performance of Si-based III-V nanolasers. In this work, we report 1.3 μm InAs/GaAs quantum-dot photonic-crystal (PhC) nanobeam lasers directly grown on complementary metal-oxide-semiconductor compatible on-axis Si (001) substrates. The continuous-wave optically pumped PhC nanobeam lasers exhibited a single-mode operation, with an ultra-low lasing threshold of ∼ 0.8 μW at room temperature. In addition, a nanoscale physical volume of ∼ 8 × 0.53 × 0.36 μm ³ (∼ 25 (λ n ⁻¹ ) ³ ) was realized through a small number of air-holes in PhC nanobeam laser. The promising characteristics of the PhC nanobeam lasers with small footprint and ultra-low energy consumption show their advanced potential towards densely integrated Si photonic integrated circuits.

Working reliably at elevated operating temperatures is a key requirement for semiconductor lasers used in optical communication. InAs/GaAs quantum-dot (QD) lasers have been considered a promising solution due to the discrete energy states of QDs. This work demonstrates temperature-insensitive and low threshold InAs/GaAs QD lasers incorporating co-doping technique, compared with p-type modulation doping. 2 mm long co-doped QD lasers exhibit a low threshold current density of 154 A cm⁻² (210 A cm⁻²) and operate at a high heatsink temperature of 205 °C (160 °C) under the pulsed (continuous-wave) mode, outperforming the p-type doped QD lasers. The results reveal that co-doping effectively enhances both high-temperature stability and threshold reduction in InAs/GaAs QD lasers, surpassing the performance of conventional p-type modulation doping. This approach offers a pathway toward cooling-free operation, making co-doped QD lasers suitable for data and telecommunication applications.

High-quality InAs/InP quantum dots (QDs) emitting at 1550 nm are indispensable to realize high-performance telecom C-band lasers. In general, a longer emission (>1550 nm) with a broad spectral character has been obtained with InAs/InP QDs. Here, we proposed the use of the indium-flush (IF) method to shorten the emission and improve the optical properties of InAs/InP QDs. By exploiting IF, the full-width at half-maximum of the room-temperature QD photoluminescence spectra is narrowed from 89.2 to 47.9 meV, with a blue shift of 300 nm (from 1824 to 1522 nm). The scanning transmission electron microscopy and electron energy loss spectroscopy results reveal the atomic-level mechanism of the IF method, which uniformly modify the height of InAs/InP QDs in a controlled manner and form distinct Al-rich and In-rich regions. Finally, InAs/InP (001) QD lasers with the IF method have been demonstrated with a low threshold current density per QD layer of 106 A/cm2. We demonstrated both in terms of mechanism model and device performance that the IF method could serve as a robust strategy for the growth of high-performance C-band InAs/InP QD lasers via molecular beam epitaxy.

We report low-threshold-current, high-yield InAs/InP quantum dot lasers in the C- and L-bands grown by metal-organic chemical vapor deposition (MOCVD). By optimizing the epitaxial growth conditions, including the introduction of a GaAs interfacial layer, we achieved more in-plane symmetric quantum dots with improved optical quality. Deep-etched ridge waveguide lasers with a 4 μm ridge width and top–top metal contacts were fabricated and characterized under pulsed injection. Low threshold currents of 17 mA and 28 mA were obtained for cavity lengths of 300 μm and 1000 μm, respectively. Temperature-dependent measurements showed lasing sustained up to 120 °C with a characteristic temperature T₀ of 74.9 K below 90 °C.