Diodes Incorporated has a section on their website for all of the SPICE models they have. If the SPICE model for your part is not available, there is a form you can use towards the bottom of the page to request one.
Here is the link:
https://www.diodes.com/design/tools/spice-models/
Diodes Incorporated also has a free downloadable simulator you can use, with a list of example schematics.
Here is the link:
https://www.diodes.com/design/tools/simulators-examples/