The Main Window

Getting started

Everything lives on one screen. The device itself goes in the layer table; everything around it sets how that device is solved.

01Four regions

The window (titled Device Structure) divides into four areas, and we shall discuss them in this order:

• Across the top — the surface boundary condition, and the one or two values it needs.
• Middle left — the layer table: the device.
• Middle right — buttons that edit the table, then the mesh setting and Run Simulation.
• Along the bottom — two panels of settings that apply to the whole solve.

02The boundary strip

Surface Boundary Conditions chooses how the top of your structure is contacted — schottky, ohmic, pinned, surface charge or contact bias. Beside it, Barrier Height and Contact Voltage supply the numbers that mode needs.

Those two fields change meaning with the mode, and one or both may be greyed out when the mode does not use them — so set the boundary condition first and fill the values afterwards. Which value to enter for each mode is covered in Surface Boundary Conditions.

03The layer table

One row per layer, and the order is the growth stack seen from outside: the top row is the surface, the bottom is the substrate. Eight columns are available — Material, Thickness (nm), Fraction (%), p-doping (cm⁻³), n-doping (cm⁻³), Dopant depth (eV), Mobility (cm²/Vs) and Contact Voltage (V).

Most structures need only the first five. Leaving a cell blank means that the material’s own default is used. The columns are described one by one in The Layer Table.

04Editing and running

To the right of the table, Add Layer appends a row at the top of the form, Insert Layer puts one above the current selection, and Delete Layer removes it. Clear Form empties the table and returns every setting to its default — useful when a stale option from a previous structure is confusing the setup.

Below those, Mesh spacing sets the grid the solver uses, from 0.05 nm to 4 nm, with 0.5 nm the default and a sensible starting point. Then Run Simulation solves the structure.

05The two settings panels

Schrodinger conditions controls the optional bound-state calculation: Find Quantised States turns it on, Start Depth and Stop Depth mark out the region to solve — both in nm — and Schrodinger Mesh sets its own finer grid, in nm or Ångströms as you choose. That units box applies to the mesh only; the depths are always in nm.

Simulation parameters holds everything else: CV calculation enables a capacitance–voltage sweep, FullyIonised decides whether dopants are all ionised, Carrier Calculations selects which carriers are included, and Temperature is in kelvin.

06The File menu

Alongside Open, Save and Save As, two entries are worth knowing early. Open Recent lists your last few structures. Open Example… opens the bundled structures, grouped into Semiconductor devices, C-V devices and Quantum devices — the quickest way to see a working structure.

Reveal Materials File and Reset Materials to Defaults… handle the editable materials database, covered in The Materials Database.