Intrinsic and extrinsic radiative recombination processes in quantum wells
Intrinsic and extrinsic photoluminescence (PL) transitions originating from wells and barriers have been observed in both undoped and Si-doped GaAsGa0.52In0.48P quantum well structures. PL excitation spectroscopy reveals that the 1.511 and 1.440 eV emissions are associated with deep impurities in the well. The dependence on the excitation density of these emissions has been investigated. The 1.440eV emission is attributed to a donor-acceptor transition involving confined levels in the well, while the 1.511 eV luminescent band is identified with the recombination of free heavy and light holes in the n = 1 confined quantum well states with a neutral deep donor. The donor and acceptor defects are presumably related to silicon and their estimated binding energies are 33 and 73 meV, respectively.
This article addresses the question regarding the ability of the Andean Multinational Enterprises for fostering intraregional inward investment within the pale of the Andean Community of Nations. The deficiencies in the philosophy behind the regime, inspired by the Regional Industrialisation Programme Model (RIPM), the insufficiency of the benefits, and the rigor of the requirements have conduced to an impairment of the regional scheme. This paper explores these problems studying the main characteristics of the transnational Andean corporations, assessing the role of the RIPM in the decay of the regime, and proposing a reform that moulds a new policy of business facilitation for regional investors. Fecha de recepcion: 15 de abril de 2005