Quantum efficiency contributions for type-II InAs/GaSb SL photodetectors

We analyze the quantum efficiency (QE) constituents of three type-II InAs/GaSb superlattice (T2SL) photodetectors with identical period lengths and different i- and p-layer thicknesses. The T2SL mid-wave detectors show the spectral response with 50% cut-off wavelength equal to 4.88 ?m at 79 K. Empirical pseudopotential method (EPM) is employed to define band structure such as bandgap energy and heavy hole?light hole (HH?LH) splitting energies. Peak responsivities are measured as 1.14, 1.20, and 1.26 A/W at 4 ?m under zero bias, with corresponding QEs of 35%, 37%, and 39%. The QEs of pin detectors are simulated by photocurrent analysis according to the Hovel Model to determine the contribution of QE components.