Investigation of the Optimum Mg Doping Concentration in p-Type-Doped Layers of InGaN Blue Laser Diode Structures (original) (raw)
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Carbon-doped AlGaAs and AlInP doped with zinc or magnesium are compared as p-cladding material for laser diodes emitting around 633 nm. Mg doping of Al(Ga)InP is linearly dependent on the Cp 2 Mg flow rate after a doping delay in which a sufficient Mg coverage of the surface is built up. Laser diodes with Mg and Zn doped cladding were fabricated, compared and analysed by secondary ion mass spectrometry. Combining a Zn-doped AlGaInP waveguide with a Mg-doped cladding layer reveals diffusion interaction between Mg and Zn and results in enhanced Mg back diffusion into the waveguide counteracting the Mg doping delay. Laser diodes emitting at the wavelength of 632 nm with an output power of more than 1 W per facet have been demonstrated using this dopant combination.
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We have demonstrated AlGaN-cladding-free m-plane InGaN-based blue laser diodes (LDs) using a novel structure that employs 50-nmthick n-and p-type In x Ga 1Àx N (x ¼ 5 {10%) as waveguiding layers. The thick, high In content InGaN waveguiding layers provided significant refractive index contrast to the GaN cladding layers, thereby eliminating the need for AlGaN cladding. Under pulsed operation, lasing was achieved at 442 nm with a threshold current density of 10 kA/cm 2 . #
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Acta Physica Polonica A, 2016
Simulations of blue and green laser diodes with InGaN quantum wells are presented. In this study, a particular emphasis on efficiency and optical power of the structures was placed. Effect of the aluminum content in an electron blocking layer on the electron overflow and efficiency is discussed. Substantial decrease of efficiency of laser diodes is reported for low aluminum levels. It is also shown that polarization charges existing in AlInGaN heterostructures grown on GaN polar direction and low ionization degree of magnesium acceptors lead to high resistance of these devices. These effects hinder the carriers from reaching an active region and consequently they impose high operating voltages.