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Henry Lee

Parameters for GaAs

I just wondering the parameters or the refernce for calculation of GaAs in Schred. Including the orientation, degenerate number, effective quantum mass, effective density of state mass, etc.

Thanks.

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    Gokula Kannan

    1.Is mz for L/X valley the mass along 111/100 direction?- the directions mentioned in the simulator are the device directions (transport/width/confinement orientation etc), the orientation that you have mentioned are the ellipsoidal(/crystallographic) directions for each of the valleys. 2.Why is not the degenerate number for L valley 8 instead of 4? Why is not the degenerate number for X valley 6 instead of 3?- we consider valley pairs, hence the degeneracy by 2 3.In your reply “Heavy hole eff. mass (same for all 3 valleys) = 0.51”, should it be “same for 3 subbands”. If it’s not, may I beg for the reason.- yes Schred takes the same hole effective mass, to calculate the valence band DOS- used to calculate the final carrier concentration. 4.Is 0.51/0.082 the quantized mass for heavy/light hole? What is the mass of density of mass for them?- It is the effective mass for the bulk GaAs – HH & LH valence bands. 5.Does Schred consider bandgap narrowing when temperature or doping concentration change?-No, it does not consider BGN. 6.By the way, can you recommand some good reference for GaAs.I find very less information about subband calculation of GsAs, so I bother you for many questions. Thank you!- Yang, T., et al. “Inversion Capacitance-Voltage Studies on GaAs Metal-Oxide-Semiconductor Structure using Transparent Conducting Oxide as Metal Gate.” Applied Physics Letters 92 (2008): 252105, I used this to compare my results with, you can check their parameters for their simulation.

    hope this helps!

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    Gokula Kannan

    Hi Lee, I assume you are asking for the simulation using Schred V2.0 The following are the parameters for the QM simulation of GaAs for that tool:

    Transport orientation = width orientation = confinement orientation = Gamma valley eff. mass (mx=my=mz) = 0.06574 L valley eff. mass: mx= 1.72750 ; my= 0.09671; mz=0.09671 X valley eff.mass: mx=1.88076; my=0.17525; mz=0.17525 Heavy hole eff. mass (same for all 3 valleys) = 0.51 Light hole eff. mass (same for all 3 valleys)= 0.082 valley offset : Gamma = 0 ; L-valley = 0.29; X-valley=0.48 valley degeneracy: Gamma = 1.0; L-valley = 4.0; X-valley = 3.0

    Do not worry about the eff. DOS mass etc, they are calculated in the program using the principal effective masses of the three valleys.

    Hope this helps, Thanks, Gokul

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      Gokula Kannan

      for some reason the orientation does not appear when enclosed withing brackets(formatting error i guess) : tranport=100; width=010; confinement = 001.

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        LM Chang

        If I use V1.0, orientation does disappear. What is the difference between 1.0 and 2.0 on GaAs simulation?

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      Henry Lee

      It is so kind that you reply these quickly. I used Schred 1.0, that’s why I wonder the parameters setting for GaAs. After reading your response, some questions should be asked: Is mz for L/X valley the mass along 111/100 direction? Why is not the degenerate number for L valley 8 instead of 4? Why is not the degenerate number for X valley 6 instead of 3? In your reply “Heavy hole eff. mass (same for all 3 valleys) = 0.51”, should it be “same for 3 subbands”. If it’s not, may I beg for the reason. Is 0.51/0.082 the quantized mass for heavy/light hole? What is the mass of density of mass for them? Does Schred consider bandgap narrowing when temperature or doping concentration change? By the way, can you recommand some good reference for GaAs. I find very less information about subband calculation of GsAs, so I bother you for many questions. Thank you!

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