Photovoltaic infrared detection with p-type graded barrier heterostructures

Abstract

Articles you may be interested inCorrelation between the performance of double-barrier quantum-well infrared photodetectors and their microstructure: On the origin of the photovoltaic effect J. Appl. Phys. 98, 044510 (2005); 10.1063/1.2006990 AlGaAs emitter ∕ GaAs barrier terahertz detector with a 2.3 THz threshold Appl. Phys. Lett. 86, 071112 (2005); 10.1063/1.1867561Quantum-well infrared photodetectors with digital graded superlattice barrier for long-wavelength and broadband detection Appl.Photovoltaic infrared 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/Al x Ga 1Àx As structures were tested as photovoltaic detectors 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 Â 10 6 Jones at a peak wavelength 1.8 lm at 300 K. Responsivity and D* increased to $1.2 V/W and 2.8 Â 10 6 Jones, respectively, at 280 K. A non-linear improvement in responsivity was observed with increased emitter thickness. V C 2012 American Institute of Physics. [http://dx.

Recent Progress on Extended Wavelength and Split-Off Band Heterostructure Infrared Detectors

“…Furthermore, the quasi-equilibrium will be built-up not only in the emitter but also in the bottom and top contact layers as long as there is photoexcitation to the SO band. The net flow of the photo-excited carriers will determine the spectral photoresponse [62,79].…”

Physics of Internal Photoemission and Its Infrared Applications in the Low-Energy Limit

“…In addition to an offset ( V ) between the barriers below and above the emitter, one of the AlGaAs barriers is graded to further increase the nonsymmetry and facilitate the transport of photoexcited holes at zero bias. The room-temperature photovoltaic operation has been reported elsewhere [52]. For comparison, different gradients of Al fractions (i.e., varies from 0.45 to 0.75 or remains a constant (Table 2)) were investigated.…”

Effect of a current blocking barrier on a 2–6 μm p-GaAs/AlGaAs heterojunction infrared detector

“…17 Furthermore, replacing the constant Al x Ga 1Àx As barrier with a graded barrier, achieved by tuning the Al mole fraction (x), was found to enable photovoltaic operation as well. 18 This is advantageous over photoconductive operation as it offers thermal noise limited performance and reduced power consumption. In this letter, we report the effect of a current blocking barrier (CBB) on a 30 period p-GaAs/Al x Ga 1Àx As IR detector with graded barriers, which shows a photoresponse at 77 K in the $2-6 lm range under photovoltaic operation.…”