A broadband radiation detector includes a first layer having a first type of electrical conductivity type. A second layer has a second type of electrical conductivity type and an energy bandgap responsive to radiation in a first spectral region. A third layer has the second type of electrical conductivity type and an energy bandgap responsive to radiation in a second spectral region comprising longer wavelengths than the wavelengths of the first spectral region. The broadband radiation detector further includes a plurality of internal regions. Each internal region may be disposed at least partially within the third layer and each internal region may include a refractive index that is different from a refractive index of the third layer. The plurality of internal regions may be arranged according to a regularly repeating pattern.