Figure 4. First and second order phonon mediated transition.

(a) Top: Two serial 1^st order processes which model the light emission calculation in indirect bandgap nanowires with ΔΩ< E_LO/LA. Bottom: A model based on a 2^nd order process presented for calculation of light emission in indirect nanowires with ΔΩ> E_LO/LA. (b) Inter-sub band (direct to indirect) electron-phonon scattering rate (s⁻¹) versus the energy starting from the bottom of direct conduction band (E−E_cmin). As can be seen scattering times for electron-LO phonon and electron-LA phonon scattering events are in the order of 1ps and 100ps, respectively. (c) Possible second order transitions from indirect conduction sub band to the valence band maximum. As it is discussed in the Results section the A→D→C event is less probable than A→B→C. Initial, intermediate and final states are represented by i, m and f, respectively.