Optical properties of (AlxGa1−x)0.52In0.48P at the crossover from a direct-gap to an indirect-gap semiconductor

Abstract

. Optical properties of (AlxGa1-x)(0.52)In0.48P at the crossover from a direct-gap to an indirect-gap semiconductor. Journal of Applied Physics, 83(4), 2241 -2249 . DOI: 10.1063 Optical properties of "Al x Ga 1؊x … 0.52 In 0.48 P at the crossover from a direct-gap to an indirect-gap semiconductor The optical properties and the dynamics of excitons and the electron-hole plasma have been studied in disordered (Al x Ga 1Ϫx ) 0.52 In 0.48 P near to the direct-to-indirect band gap crossover. In particular we have investigated three epitaxial layers grown by solid-source molecular beam epitaxy with varying Al content x. Two of them have compositions in the immediate vicinity of the crossover point, the other is assigned to the indirect-gap regime. Both direct and indirect recombination processes contribute to the photon emission from the material. Since the relative importance of the different recombination processes depends strongly on temperature, excitation intensity, and excitation pulse duration, the processes can be identified by changing these parameters. As a result, we can determine the relative alignment of the conduction band minima and the distribution of the electrons among them. At high excitation levels the two crossover samples show stimulated emission at a photon energy of ϳ2.29 eV, i.e., in the green spectral range. Using the variable stripe length method, we find an optical gain of up to ϳ600 cm Ϫ1 at excitation levels of ϳ350 kW/cm 2 . Stimulated emission involves direct recombination. This conclusion is reached from the experiments and from line-shape modeling, including a self-consistent treatment of populations and renormalization of the conduction band minima.

650-nm AlGaInP multiple-quantum-well lasers grown by metalorganic chemical vapor deposition using tertiarybutylphosphine

“…In indirect band-gap materials, the phonon replicas are more likely to be observed, therefore, the lower energy peaks probably originate from the phonon replica of the main peak because the energy difference between the main peak and the weak peak agrees fairly well with the energies of LO phonons in AlGaInP. [21][22][23] For Ga 0.52 In 0.48 P and (Al 0.3 Ga 0.7 ) 0.52 In 0.48 P, very weak low-energy peaks are similarly observed, as shown in Fig. 1, with an energy difference of some 47 meV between the weak peak and the respective main peak.…”

Conduction band offset in the AlxGayIn1−x−yP/Ga0.52In0.48P system as studied by luminescence spectroscopy

“…For example, some of these devices involve a strained In 0.2 Ga 0.8 As well when grown on a GaAs substrate. [15][16][17][18] If the targeted application does not require the growth of thick layers, there is no reason to restrict the composition of the AlGaInP barrier to strain-free materials, even if this implies an increased complexity of the structure. [1][2][3] Up until now, the quaternary lattice matched on GaAs, that is (Al z Ga 1Ϫz ) 0.52 In 0.48 P, has been mainly studied.…”