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 J_th =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 η_ext ∼70%, a value equal to the η_ext 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.