Since the 1960s I have made and played mountain dulcimers, or fretted dulcimers, and they are featured on the CD Moonlight on the River.
While my early mountain dulcimers were wood, and wood mountain dulcimers are played on my recordings, for years I have experimented with dulcimers made partly or largely of carbon fiber composite. Carbon soundboards can be strong even when very thin, resulting in a responsive and warm tone. My dulcimers are designed for responsiveness and volume to suit the melodic fingerpicking styles I like to play. Critical design features include the soundboard, the bracing, and the weight and stiffness of the fretstaff. Carbon can help achieve design goals with better durability as well as resistance to moisture and humidity problems.
I've done a lot of experiments on amplifying dulcimers with pickups and microphones, including building my own pickups. Here is some useful information. Amplifying Mountain Dulcimers