TFT 器件模拟：DD 模拟的挑战与优化

Translation: Currently, the dd simulation is being used to solve TFT devices, with the main requirements being the I-V curve, hysteresis phenomenon, solution speed, and solution stability.

1. Attempts have been made to add a defect state model, but the Id-Vg curve is not smooth and has large jumps.

2. The solution speed is too slow. For example, it takes two loops to solve the Id-Vg curve for Vd=-5V and Vg=-5V:

for(double Vd = 0; Vd > -5; Vd+=Vd_step){
  for(double Vg = 0; Vg > -5; Vg+=Vg_step){
    dd_simulator = set_initial_guess(...);
    ...
  }
}

The previous calculation results are used as the initial values for the next step. Moreover, Vd_step and Vg_step can only be between 0 and 0.5 and cannot be too large. These settings result in slow solution speed and a faster method is needed.

3. What model should be used to simulate the hysteresis phenomenon?

4. The Newton iteration in viennashe is only designed for she simulation. A Newton iteration algorithm or other iteration algorithms need to be added to the dd simulation.