Quantum dot infrared photodetector enhanced by surface plasma wave excitation.

Up to a thirty-fold detectivity enhancement is achieved for an InAs quantum dot infrared photodetector (QDIP) by the excitation of surface plasma waves (SPWs) using a metal photonic crystal (MPC) integrated on top of the detector absorption region. The MPC is a 100 nm-thick gold film perforated with a 3.6 microm period square array of circular holes. A bare QDIP shows a bias-tunable broadband response from approximately 6 to 10 microm associated with the quantum confined Stark (QCS) effect. On the other hand, an MPC-integrated QDIP exhibits a dominant peak at 11.3 microm with a approximately 1 microm full width at half maximum and the highly enhanced detectivity at the bias polarity optimized for long wavelength. This is very different from the photoresponse of the bare QDIP but fully consistent with the direct coupling of the QDs in the detector absorption region to the SPWs excited at the MPC/detector interface by incident photons. The SPW resonance wavelength, lambda, for the smallest coupling wavevector of the array in the MPC is close to 11.3 microm. The response also shows other SPW-coupled peaks: a significant peak at 8.1 microm (approximately lambda/radical2) and noticeable peaks at 5.8 microm (approximately lambda/2) and 5.4 microm (approximately lambda/ radical5) which correspond to higher-order coupling wavevectors. For the opposite bias, the MPC-integrated QDIP shows the highest response at 8.1 microm, providing a dramatic voltage tunability that is associated with QCS effect. SPWs propagate with TM (x, z) polarization along the MPC/detector interface. The enhanced detectivity is explained by these characteristics which increase both the effective absorption cross section with propagation and the interaction strength with TM polarization in the coupling to the QDs. Simulations show good qualitative agreement with the observed spectral behavior.

[1]  Rui Qiang,et al.  Modeling Electrical Properties of Gold Films at Infrared Frequency Using FDTD Method , 2004 .

[2]  Xiang Zhang,et al.  Plasmon lasers at deep subwavelength scale , 2009, Nature.

[3]  Andreas Stintz,et al.  Three-color (λp1∼3.8 μm, λp2∼8.5 μm, and λp3∼23.2 μm) InAs/InGaAs quantum-dots-in-a-well detector , 2003 .

[4]  Mid-infrared transmission enhancement through sub-wavelength metal hole array using impedance-matching dielectric layer , 2009 .

[5]  E. A. Patten,et al.  Fabrication and characterization of two-color midwavelength/long wavelength HgCdTe infrared detectors , 2006 .

[6]  C. H. Wang,et al.  Polarization dependence of intraband absorption in self-organized quantum dots , 1998 .

[7]  Kotaro Kajikawa,et al.  Principles of Nano-Optics: Surface plasmons , 2006 .

[8]  Azzouz Sellai,et al.  Quantum efficiency in GaAs Schottky photodetectors with enhancement due to surface plasmon excitations , 2002 .

[9]  Sanjay Krishna,et al.  Demonstration of a 320×256 two-color focal plane array using InAs/InGaAs quantum dots in well detectors , 2005 .

[10]  Numerical Study of Near-Infrared Photodetectors with Surface-Plasmon Antenna for Optical Communication , 2008 .

[11]  S. Brueck,et al.  Enhanced quantum efficiency internal photoemission detectors by grating coupling to surface plasma waves , 1985 .

[12]  E. Finkman,et al.  Midinfrared absorption and photocurrent spectroscopy of InAs/GaAs self-assembled quantum dots , 2001 .

[13]  Dimitris G. Manolakis,et al.  Detection algorithms for hyperspectral imaging applications , 2002, IEEE Signal Process. Mag..

[14]  K. Malloy,et al.  Metallic inductive and capacitive grids: theory and experiment. , 2002, Journal of the Optical Society of America. A, Optics, image science, and vision.

[15]  E. Dereniak,et al.  Infrared Detectors and Systems , 1996 .

[16]  T. Ebbesen,et al.  Light in tiny holes , 2007, Nature.

[17]  John P. Kerekes,et al.  Modeling of LWIR hyperspectral system performance for surface object and effluent detection applications , 2001, SPIE Defense + Commercial Sensing.

[18]  Federico Capasso,et al.  Plasmonic laser antenna , 2006 .

[19]  A. Goetz,et al.  Terrestrial imaging spectroscopy , 1988 .

[20]  Arnold C. Goldberg,et al.  Application of dual-band infrared focal plane arrays to tactical and strategic military problems , 2003, SPIE Optics + Photonics.