Self-absorption effects of internal luminescence in one-dimensional nanowires with and without localized states

Abstract

<p>Recent rigorous demonstration of self-absorption (SA) effects of internal luminescence in solids [H. G. Ye et al. Sci. Bull. 62, 1525 (2017)] has opened a breach in the solid wall behind which the SA processes and effects occur but cannot be directly probed inside the solid. Herein, we attempt to present a further theoretical consideration of the SA effects of internal luminescence occurring inside a nanowire with Urbach band-tail states. The consideration begins with an ideal luminescence spectrum with δ-line shape and then goes to the cases of luminescence spectra with Lorentzian, Gaussian, and localized-state ensemble (LSE) line shapes, respectively. A quantitative consideration of the SA effects in the spectral features of external luminescence spectra along with the nanowire axis is established for the variables of temperature, transmission distance, and photon energy. Generally, it is found that the self-absorption of internal luminescence can have a significant impact on the spectral features of external luminescence, depending on the three above-mentioned variables. In particular, the influence of SA on the three key spectral parameters, including intensity, peak position, and full width at half maximum (FWHM) of external LSE luminescence, is unveiled, providing a quantitative explanation for a few experimental phenomena reported in the literature. In addition, some interesting phenomena, i.e., nearly no peak shift with increasing the transmission distance, etc., have been predicted. These results more deeply establish the theoretical foundation of self-absorption, which is of positive significance for the regulation and enhancement of optoelectronic devices.</p>