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Passivation of type II InAs/GaSb superlattice photodetectors with atomic layer deposited Al2O3

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2012-04-27
Salihoglu, Omer
Muti, Abdullah
Kutluer, Kutlu
Tansel, Tunay
Turan, Raşit
KOCABAŞ, COŞKUN
AYDINLI, ATİLLA
We have achieved significant improvement in the electrical performance of the InAs/GaSb midwave infrared photodetector (MWIR) by using atomic layer deposited (ALD) aluminium oxide (Al2O3) as a passivation layer. Plasma free and low operation temperature with uniform coating of ALD technique leads to a conformal and defect free coverage on the side walls. This conformal coverage of rough surfaces also satisfies dangling bonds more efficiently while eliminating metal oxides in a self cleaning process of the Al2O3 layer. Al2O3 passivated and unpassivated diodes were compared for their electrical and optical performances. For passivated diodes the dark current density was improved by an order of magnitude at 77 K. The zero bias responsivity and detectivity was 1.33 A/W and 1.9 x 10(13) Jones, respectively at 4 mu m and 77 K. Quantum efficiency (QE) was determined as %41 for these detectors.