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effective masses in Interconnect TWLM


    • pi2022

      Dear All,

      How are the quantum well and barrier effective masses (twlm.QW_eff_mass and twlm.QB_eff_mass) defined in Lumerical TWLM laser model?

      Are they just electron effective masses in these materials?

      thank you

    • Guanhui Wang
      Ansys Employee

      Hi ,


      I believe this is the case. 

    • Guilin Sun
      Ansys Employee

      Apology to reply you late.

      The mass definition is usual which can be found in some textbooks.

      These effective masses are used as parameters in the thermionic leakage model to calculate carrier escape rate over the barriers. In addition to effective masses, the other parameter important for thermionic emission (i.e. escape rate) is the barrier height. The escape rate can be defined in the quantum well (QW) and at the SCH barrier. The total escape rate is 1/tau_escape = 1/tau_escape_electron + 1/tau_escape_hole. Since usually one term is dominant, the user can define effective mass and barrier height for either electron or hole, depending which leakage is more dominant. For QW escape rate the parameters used are the QW effective mass and barrier height, while for the SCH escape the important parameters are the quantum barrier (QB) effective mass and the SCH barrier height.

      Additionally, once you decide whether to need electron or hole effective mass according to the above explanation, you can potentially use our electrical material database, create III-V alloy material as semiconductor and check the effective mass value in the material properties in the object tree. Or you can use your own value of effective mass for the given material in the quantum well and barrier.


      I hope this clarifies both the issues.


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