An AIX-200 horizontal reactor was used for the epitaxial growth with standard precursors at a high temperature of 710☌ and a reactor pressure of 100 mbar to achieve a high density of QDs. Our QD structures were grown by metal-organic vapor-phase epitaxy (MOVPE) on the Si-doped (100)-GaAs substrate with a misorientation of 6°-towards the A direction. The experimental results provide detailed insight into the optical properties of the QD lasers based on this material system, which has great significance for the further development in the shorter wavelengths. In this paper, we present experimental investigations of the temperature-dependent optical gain and lasing characteristics of a single-layer InP/AlGaInP QD edge emitting laser at 660 nm. Even though a lot of investigations have been done for the InP/GaInP QD lasers with the lasing wavelengths longer than 710 nm, there are few reports for the shorter wavelengths. The self-assembled InP QDs in the (Al xGa 1- x) 0.52In 0.48P (it is named as Al xGaInP below) material can extend the emitting wavelength to cover above spectral range by varying not only the epitaxial growth conditions, but also the Al-content of the barriers. In the visible spectrum, the range between 630 nm and 780 nm has great potentials for the applications of biotherapy, data storage, optical fiber communication, and UV-laser generation. Meanwhile, the QDs can provide more possibilities to tune the emitting wavelengths, which is difficult to realize on QW and bulk materials platforms. Compared to quantum well (QW) and bulk structures, the QD devices typically have higher differential gain, lower threshold current density, higher characteristic temperature, and ultrafast carrier capture dynamics.
Since being proposed by Arakawa and Sakaki in 1982, semiconductor quantum dots (QDs) as the gain medium in the laser sources have attracted great interest in many applications, owing to the excellent properties from their discrete energy levels and 3D confinement of the carriers.
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