Semiconductor lasers directly grown on silicon offer great potential as critical components in high-volume, low-cost integrated silicon photonics circuits. Although InAs/InP quantum dash (QDash) lasers on native InP substrate emitting at 1.5 μm (C-band) have demonstrated notable performance, the growth of InAs/InP QDash lasers on silicon remains undeveloped because of the 8% lattice mismatch between InP and silicon. Here we report advances of growth techniques leading to the first C-band room-temperature continuous-wave electrically pumped QDash lasers on CMOS standard (001) silicon substrates by metalorganic chemical vapor deposition. A correlation between various material characterizations and device performance is analyzed for different QDash laser structures grown on planar nominal (001) silicon. With the optimized QDash growth and improved fabrication process, the lowest threshold current density of 1.5kA/cm2 was determined on an 8μm×1.5mm device on planar silicon with a single facet output power exceeding 14 mW. The device results illustrate the good material quality of the QDash lasers grown on silicon, suggesting potential applications for other active components of photonic integrated circuits, such as semiconductor optical amplifiers, modulators, and photodetectors.