An organic solid state injection laser

We report on electrically driven amplified spontaneous emission and Lasing in tetracene single crystals using field-effect electrodes for efficient el ectron and hole injection. For Laser action, feedback is provided by reflec tions at the cleaved edges of the crystal resulting in a Fabry-Perot resona tor. Increasing the injected current density above a certain threshold valu e results in the decreasing of the spectral width of the emission from 120 millielectron volts to Less than 1 millielectron volt because of gain narro wing and eventually Laser action. High electron and hole mobilities as well as balanced charge carrier injection Lead to improved exciton generation i n these gate-controlled devices. Moreover, the effect of charge-induced abs orption is substantially reduced in high-quality single crystals compared w ith amorphous organic materials.