Low-threshold high-efficiency AlGaAs-GaAs double-heterostructure injection lasers grown on Si substrates by metalorganic chemical vapor deposition

Abstract

We have fabricated low-threshold, high-quantum-efficiency, room-temperature AlGaAs-GaAs double-heterojunction injection lasers from epitaxial structures grown by metalorganic chemical vapor deposition directly on Si substrates. These devices have broad-area (125 μm×250 μm) pulsed threshold current densities as low as Jth =3.5 kA/cm2 at ∼23 °C. Ridge-waveguide stripe-geometry lasers (5 μm×250 μm) have pulsed threshold currents as low as 130 mA at ∼23 °C. These stripe-geometry lasers have total external differential quantum efficiencies as high as ηext ∼70%, a value equal to the ηext measured for similar double-heterostructure lasers grown on GaAs substrates. These are the lowest threshold currents and highest external quantum efficiencies yet reported for lasers grown on Si substrates.