AlGaN alloys have emerged as the most promising semiconductor compounds for deep-ultraviolet (DUV) applications. Indeed, electronic bandgap engineering can be performed by changing the alloy composition, enabling the production of semiconductor light sources covering most of UVA, UVB and UVC spectra. The main interest in pushing the emission toward such short wavelengths relies on the wide variety of applications ranging from the biomedical field, for dermatological therapy (i.e. psoriasis, vitiligo), to UV curing (mainly UVA and UVB), to plant illumination systems for green-houses (UVB), and water/surface purification and disinfection (UVC and below). The main limitation of a realistic implementation of deep-UV emitting devices relies in the thermal management.