A conjecture on a quantum limit of semiconductor lasers
  A relationship between the maximum operating temperature of semiconductor lasers and their emission wavelength is conjectured. The conjecture is supported by a wide variety of existing experimental data for visible and infrared double heterojunction and quantum well lasers, quantum cascade lasers, as well as more esoteric devices such as Type-II antimonide-based mid-infrared and p-Ge and impurity-based Terahertz devices. The relationship developed may enable the ultimate performance of mid- and far-infrared, as well as Terahertz semiconductor lasers to be predicted. 
P. Harrison and E. E. Orlova