Photovoltaic infrared detection with p-type graded barrier heterostructures

Photovoltaicinfrared detectors have significant advantages over photoconductive detectors due to zero bias operation, requiring low power and having reduced low frequency noise. They also exhibit no thermally assisted tunneling currents, leading to higher operating temperatures. p-type emitter/graded barrier GaAs/AlxGa1 12xAs structures were tested as photovoltaicdetectors in the infrared region, operating under uncooled conditions and without an applied bias voltage. A photovoltaic responsivity of 450 mV/W was obtained with a detectivity (D*) of 1.2\u2009 7\u200910^6 Jones at a peak wavelength 1.8 \u3bcm at 300 K. Responsivity and D* increased to 3c1.2 V/W and 2.8\u2009 7\u200910^6 Jones, respectively, at 280 K. A non-linear improvement in responsivity was observed with increased emitter thickness.Peer reviewed: YesNRC publication: Ye