Short-Period Strain-balanced GaAs 1-x N x /InAs(N) Superlattices Lattice-matched to InP(001): a new material for 0.4-0.6
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Short-Period Strain-balanced GaAs1-x Nx/InAs(N) Superlattices Lattice-matched to InP(001): a new material for 0.4-0.6 eV mid IR applications L. Bhusal 1,2, A. Alemu1 and A. Freundlich1,2 Photovoltaics and Nanostructures group, Texas Center for Superconductivity and Advanced Materials, University of Houston, 4800 Calhoun, TX-77204, USA 2 Physics Department, University of Houston, 4800 Calhoun, TX-77204, USA 1
ABSTRACT A theoretical and experimental investigation of electronic band structure (Γ-point) of strain balanced GaAs1-xNx/InAs1-xNx short period superlattice on InP is performed. A six-band Kane Hamiltonian and band anti-crossing models, modified for the strain effects are used to describe the electronic states of the highly strained zincblende GaAs1-xNx and InAs1-xNx ternaries. Operating wavelengths of these heterostructures are predicted to extend beyond 2 µm. Preliminary photoluminescence results of the chemical beam epitaxially grown sample are shown to be consistent with the theoretical predictions.
INTRODUCTION During the 1990s, nitrogen containing dilute III-N-V alloys, such as Ga(In)NAs and Ga(In)NP have emerged as a subject of considerable research interest. A significant effect of replacing group-V element (As or P) with small amount of nitrogen (N) is extremely large bandgap bowing, and narrowing of the direct energy gap with increasing N content. Combining this novel property of dilute III-V nitrides with recent years of success in the development of quantum structures, like short period superlattices, self assembled quantum dots, quantum wires, etc. opens a wide path for new innovations and research for the applications in optoelectronic devices such as mid-infrared lasers, long-wavelength infrared detectors, terahertz devices, modulators, highly efficient multi-junction tandem solar cells and thermophotovoltaics [1-7]. Most of the work has concentrated on the development of Ga(In)AsN alloys lattice-matched to the GaAs substrate [1-5]. The idea of short period strain balanced superlattice GaAs1-xNx /InAs on InP had been introduced to tune the emission/absorption of the material ~0.4-0.6eV [710]. In this work we have extended the previous study to GaAs1-x Nx / InAs1-x Nx strain balanced superlattice on InP (001). The study covers the range of practically achievable N compositions (x
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