Impact of growth rate on the quality of ZNS-MQW InGaAsP/InP laser structures grown by LP-MOVPE

Abstract

We investigated the influence of the growth rate on the quality of zero-netstrained InGaAsP/InGaAsP/InP multiquantum well structures for 1.55 µm emission grown by low pressure metalorganic vapor phase epitaxy. The samples consisted of fixed compressive strained wells (ε = +1%) and tensile strained barriers (ε = -0.5%) grown with different quaternary bandgap wavelengths (λ B = 1.1-1.4 µm). Using higher growth rates, we obtained for the first time high quality zero net strained multi quantum well structures, regardless having constant group V composition in the well and barriers. The samples were analyzed by x-ray diffraction, photoluminescence and atomic force microscopy techniques. The amplitude of surface modulation roughness along [011] direction decreased from 20 nm to 0.53 nm with increasing growth rate and/or quaternary compositions grown outside the miscibility gap. A new deep PL broad emission band strongly correlated with the onset of wavy layer growth is also reported. Broad area and ridge waveguide lasers with 10 wells exhibited low losses (34 cm -1 ) and low threshold current densities at infinite cavity length (1020 A·cm -2 and 1190 A·cm -2 , respectively).

Metalorganic Vapor Phase Epitaxial Growth Parameter Dependence of Phase Separation in Miscibility Gap of InGaAsP

“…We found that the growth rate dependence of phase separation is opposite of those reported in the previous papers. [9][10][11] Epitaxial layers of InGaAsP were grown on (100) exact and 10 off toward h111iA GaAs substrates at the same time in a horizontal MOVPE system. The growth temperature was 630 C and the chamber pressure was 60 hPa.…”

“…As for vapor phase growth, however, there are some reports that gas-phase-related parameters such as growth rate and V/III flow ratio can affect the immiscibility of mixed crystals; in molecular beam epitaxy (MBE) growth, 8,9) the MOVPE growth of Sb-related materials, 10) and the MOVPE growth of highly strained InGaAsP layers on InP substrates. 6,11) As for MOVPE growth of InGaAsP on GaAs substrates, phase separation easily occurs even in nonstrained layers. 5) However, the growth parameter dependence of phase separation has not been investigated in this system except for the dependences on growth temperature and substrate misorientation.…”

“…These results seem to indicate that similar approaches are effective for the growth of materials in the miscibility gap. Calvalho et al 11) shows that an increase in growth rate can also suppress surface undulation in the growth of strain-compensated InGaAsP superlattices. This approach also aims for the suppression of surface migration by increasing growth rate.…”