What Charge Monitors are Available?

Date	Category
2025-08-26 10:06:59	Charge

Currently, there are three monitors available:

• SteadyPotentialMonitor:

  • This monitor records the electric potential (\(\Phi\)).

import tidy3d as td

voltage_monitor_z0 = td.SteadyPotentialMonitor(
    center=(0, 0.14, 0),
    size=(0.6, 0.3, 0),
    name="voltage_z0",
    unstructured=True,
)

• SteadyFreeCarrierMonitor:

  • This monitor records the steady-state free carrier concentrations (\(J_n\) for electrons and \(J_p\) for holes).

import tidy3d as td

voltage_monitor_z0 = td.SteadyFreeCarrierMonitor(
    center=(0, 0.14, 0),
    size=(0.6, 0.3, 0),
    name="voltage_z0",
    unstructured=True,
)

• SteadyCapacitanceMonitor:

  • This monitor records the small-signal capacitance within the area or volume defined by the monitor.

import tidy3d as td

capacitance_global_mnt = td.SteadyCapacitanceMonitor(
    center=(0, 0.14, 0),
    size=(td.inf, td.inf, 0),
    name="capacitance_global_mnt",
)

For an application example of Charge monitors, please refer to this example.

Note that currents are naturally computed for DC isothermal simulations without the need for a monitor. They can be accessed via the charge_data.device_characteristics.steady_dc_current_voltage object, as illustrated in this example.