According to various embodiments, a photodetector including a first contact layer, a second contact layer, an active region, and a photonic crystal resonant cavity is disclosed. The photonic crystal resonant cavity can operate as a resonant structure to enhance the response of the photodetector at one or more wavelengths. In various embodiments, the photodetectors including a photonic crystal resonant cavity can, for example, demonstrate increased responsivity and quantum efficiency, lower the operating temperature, and/or be used to form a hyperspectral detector.