Current-injected narrow linewidth emissions from organic-crystal light-emitting transistors having a diffraction grating

We have fabricated light-emitting field-effect transistors (LEFETs) using p-type organic crystals directly grown onto a two-dimensional polymer diffraction grating made of a triangular lattice of circular air holes. An n-type organic thin film was inserted between the crystal and the metal electrode. Distinct current-injected spectrally narrow linewidth emissions (NLEs) were observed under application of alternating-current voltages to the gate contact. The NLE peaks were related to the combined refractive index of the p-type crystal and the grating. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)