XBn barrier detectors for high operating temperatures

“N” structure for type-II superlattice photodetectors

“…To this end combination of bulk and superlattice barriers with superlattice absorbers are being intensively studied. [6][7][8][9][10][11] Lattice matching using appropriate material combinations with favorable conduction band offsets for both electrons and holes is possible. A unipolar barrier with band gap larger than that of the absorber region reduces diffusion currents while maintaining the photocurrent level.…”

“…8 Klipstein et al demonstrated an XBn design reaching blip temperature of 160 C and quantum efficiency of 70% with cutoff wavelength of 4.1 lm. 9 Further, complex supercells containing designs like "W" structure 10 and "M" structure 11 have been introduced as bipolar barriers with various degrees of performance. Besides reducing the dark current and increasing the differential resistance-area product, "M" design also aims to increase the overlap integral between electron and hole wavefuntions, intending to attain higher optical absorption.…”

Barrier Detectors Versus Homojunction Photodiode

“…The diffusion current normally may be expressed by the relation ~ T 3 exp(-Eg0/kBT), where Eg0 stands for the band gap extrapolated to the zero temperature T, kB is the Boltzmann's constant. The GR current varies as ~ T 3/2 exp(-Eg0/2kBT) and is considered to be dominated by the generation of electrons and holes by SRH traps in the depletion region [20]. Assuming that the nBn detector is nearly lacking of the depletion region, the GR contribution to the net dark current from the absorber layer is limited.…”

Mid-Wavelength Infrared nBn for HOT Detectors

“…5,7,10,[13][14][15][16] While the idea of the nBn design originated with bulk materials, 5,17 its demonstration using T2SL-based materials facilitates experimental realization of the nBn concept with improved control of band-edge alignments. 18 Unipolar barriers can also be inserted into the conventional p-n photodiode architecture.…”