Direct evidence of the self-compression of injected electron-hole plasma   in silicon
  A surface distribution of the electroluminescence intensity of silicon p-n light emitting diodes is obtained under space scanning experiments at room temperature. An emitting surface of the diodes, represented by a few small bright emitting dots and a weakly emitting area outside the dots, serves as a direct evidence of the self-compression of injected electron-hole plasma in silicon. The plasma self-compression explains concentration of injected carriers into one or a few strongly emitting plasma drops. 
Pavel Altukhov and Evgenii Kuzminov