Spontaneous and Stimulated Emission from GaAs Diodes with Three-Layer Structures

Abstract

The electrical and optical properties of GaAs diodes with three‐layer structures are described. The center layer was either n‐type (n⁺‐n‐p⁺ diodes), semi‐insulating (n⁺‐i‐p⁺ diodes) or p‐type (n⁺‐p‐p⁺ diodes). The spontaneous emission lines from n⁺‐n‐p⁺ diodes were studied in detail. For a low doping level of the n layer they can be interpreted by assuming hole recombination on the n side of the p⁺‐n junction. Lasing occurred in a 1.5‐eV line and in second‐order transverse modes. Small vertical beamspreads were observed. Optical gain factor and laser losses are discussed. Stimulated emission was not obtained when the n layer was very thick. n⁺‐i‐p⁺ diodes had a Cr‐doped middle region and showed a negative resistance at 300°K. Lasing occurred in the 1.48‐eV line. n⁺‐p‐p⁺ diodes showed emission lines attributed to tunneling. Lasing occurred in the 1.48‐eV line. The temperature dependence of the threshold current density is discussed.