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Ruddlesden-Popper halide perovskites are 2D solution-processed quantum wells with a general formula A2A'n-1MnX3n+1, where optoelectronic properties can be tuned by varying the perovskite layer thickness (n-value), and have recently emerged as efficient semiconductors with technologically relevant stability. However, fundamental questions concerning the nature of optical resonances (excitons or free carriers) and the exciton reduced mass, and their scaling with quantum well thickness, which are critical for designing efficient optoelectronic devices, remain unresolved. Here, using optical spectroscopy and 60-Tesla magnetoabsorption supported by modeling, we unambiguously demonstrate that the optical resonances arise from tightly bound excitons with both exciton reduced masses and binding energies decreasing, respectively, from 0.221 m0 to 0.186 m0 and from 470 meV to 125 meV with increasing thickness from n equals 1 to 5. Based on this study we propose a general scaling law to determine the binding energy of excitons in perovskite quantum wells of any layer thickness. [ABSTRACT FROM AUTHOR]

We report first-principle density functional calculations of the spontaneous polarization, piezoelectric stress constants, and elastic constants for the III-V wurtzite structure semiconductors InAs and InP. Using the density functional theory implemented in the VASP code, we obtain polarization values-0.011 and-0.013 C/m, and piezoelectric constants e ( e) equal to 0.091 (-0.026) and 0.012 (-0.081) C/m for structurally relaxed InP and InAs respectively. These values are consistently smaller than those of nitrides. Therefore, we predict a smaller built-in electric field in such structures. [ABSTRACT FROM AUTHOR]

An efficient mechanical and electronic axial approximation of the strained 8 × 8 Hamiltonian is proposed for zinc-blende nanostructures with a cylindrical shape on (100) substrates. Vertically stacked InAs/InP columnar quantum dots (CQDs) for polarization insensitive semiconductor optical amplifier (SOA) in telecommunications applications are studied theoretically. Non-radiative Auger processes in InAs/InP quantum dots (QDs) are also investigated. It is shown that a multiband approach is necessary in both cases. [ABSTRACT FROM AUTHOR]