Impact of interface roughness on perpendicular transport and domain   formation in superlattices
  A microscopic calculation of the perpendicular current in doped multiple quantum wells is presented. Interface roughness is shown to affect the resonant transitions as well as to cause a nonresonant background current. The theoretical characteristics exhibit several branches due to the formation of electric field domains in quantitative agreement with experimental data. 
Andreas Wacker and Antti-Pekka Jauho (Mikroelektronik Centret,   Danmarks Tekniske Universitet, Lyngby, Denmark)