Research on GaInAAs semiconductor alloy for temperature-insensitive wavelength semiconductor lasers

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Research of laser diodes whose wavelength do not fluctuate with ambient temperature variation is performed. A new semiconductor GaNAsBi alloy which has been created by our laboratory, was grown on n-GaAs substrate by molecular beam epitaxy (MBE) using solid Ga, Bi, As sources and nitrogen radicals generated from N_2 gas in rf plasma. The temperature dependency of its energy band is shown to be very small, 0.16meV/K, which is confirmed by photoluminescence (PL) measurement. The PL optical output from a GaNAsBi layer, which has two cleaved facets for Fabry-Perot cavity, was measured as a function of excitation optical power using 0.98μm pump laser as an excitation light source. Nonlinear increase in PL intensity has been observed at 100K by 400mW pump laser intensity. As excitation optical power of pump laser is limited, lasing was-not confirmed. To measure electroluminescence(EL) characteristics of GaNAsBi diodes, GaNAsBi/GaAs double-heterostructure (DH) was also grown by MBE. SiO_2 stripe laser structure was fabricated using conventional processing technique and sputtered SiO_2 film. The EL of the DH diodes was measured under pulse current condition at several temperatures using cryostat. The temperature dependence of the EL peak energy of the DH diodes was 0.09 nm/K in the temperature range of 100- 300K, much smaller than the temperature dependence of EL emission from GaInAsP/ InP DH diodes. The temperature dependence of the absorption edge is also measured and shown to be about 0.2 meV/K in the temperature range of 193-300K. This temperature-insensitive wavelength absorption characteristics of GaN_yAs_<1xy>Bi_x/GaAs DH diodes is also applicable to semiconductor optical modulator.Based on the research, a new semiconductor laser with small wavelength fluctuation with temperature variation might be obtainable by improving GaNAsBi alloy quality and laser processing technology.