Implementations of the subject matter described herein relate to sensors including piezoelectric micromechanical ultrasonic transducer (PMUT) sensor elements and arrays thereof. The PMUT sensor elements may be switchable between a non-ultrasonic force detection mode and an ultrasonic imaging mode. A PMUT sensor element may include a diaphragm that is capable of a static displacement on application of a force and is capable of a dynamic displacement when the PMUT sensor element transmits or receives ultrasonic signals. In some implementations, a PMUT sensor element includes a two dimensional-electron gas structure on the diaphragm. The sensors may further include a sensor controller configured to switch between a non-ultrasonic force detection mode and an ultrasonic imaging mode for one or more of the PMUT sensor elements, wherein an applied force is measured in the non-ultrasonic force detection mode and wherein an object is imaged ultrasonically during the ultrasonic imaging mode.