Application of superlattice bandpass filters in 10 μm infrared detection

Recently, experimental evidence has revealed that the energy distribution of the dark current in a typical multiple quantum well GaAs infrared detector is extremely broad, in contrast to the narrowly distributed photocurrent. In this letter, we present the current transfer ratio of an infrared hot‐electron transistor with a superlattice collector filter. From the current transfer characteristics, we demonstrate that the superlattice is able to collect electrons with specific energy against a broad background. The energy filtering characteristics can be attributed to the underlying band structure of the superlattice. When the filter is applied to infrared radiation detection, the detectivity of the transistor is improved.