Temperature performance analysis of terahertz quantum cascade lasers:   Vertical versus diagonal designs
  Resonant phonon depopulation terahertz quantum cascade lasers based on vertical and diagonal lasing transitions are systematically compared using a well established ensemble Monte Carlo approach. The analysis shows that for operating temperatures below 200 K, diagonal designs may offer superior temperature performance at lasing frequencies of about 3.5 THz and above; however, vertical structures are more advantageous for good temperature performance at lower frequencies. 
Alp\'ar M\'aty\'as, Mikhail A. Belkin, Paolo Lugli, and Christian   Jirauschek
cond-mat.mes-hall physics.optics