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GaSb/GaAs quantum dots (QDs) and quantum rings (QRs) are investigated. By using periodical growth interrupts, precise coverage control can be achieved for GaSb QD growth by using a single Ga source. With direct As irradiation to the substrate surface during the post soaking time, the soaking time can be effectively reduced while full ring morphologies and room-temperature QR luminescence can still be obtained by using this method.

In this letter, a 256/spl times/256 midwavelength infrared focal plane array (FPA) based on 30-period InAs-GaAs quantum-dot infrared photodetectors (QDIPs) is fabricated. The demonstrated original real-time nonuniformity corrected thermal images of hot soldering iron head with 30-Hz frame rate for the FPA are observed. Without additional light-coupling scheme, the QDIP FPA module is first operated at temperatures higher than 135 K under normal-incident condition with a 30/spl deg/ field of view and f/2 optics. For single device performances, a similar QDIP device with a 30-period InAs-GaAs QD structure is fabricated under the same processing procedure. High specific detectivity D/sup */ 1.5/spl times/10/sup 10/ cm/spl middot/Hz/sup 1/2//W and low noise current density 5.3/spl times/10/sup -13/ A/Hz/sup 1/2/ at applied voltage 0.3 V are observed.

In this work, the 30 stacked InAs/GaAs quantum dot infrared photodetector (QDIP) structure was grown by solid-source molecular beam epitaxy technique and demonstrated with dual-band mid- (2.7~5.6μm) and long- (7.5~13.5μm) wavelength normal-incident detections without grating and passivated process for 256×256 FPA. The 256 ×256 QDIP FPA hybridized with snapshot-mode ROIC was mounted in a 68 pin leadless ceramic chip carrier which was put in the testing dewar with IR optical cold spectral filters of the 2.9~5.5μm and 6.5~14.5 μm for the dual-band IR detections, respectively. The testing scheme for thermal imaging uniformity of the InAs/GaAs QDIP focal plane array (FPA) has been proposed and calibrated using a plane-typed blackbody source of a high temperature of 373±1K and lower ambient temperature for the two-point temperature correction. The averaged of specific detectivity (D*) and operability of the QDIP FPA have reached 1.5×10 10 cm-Hz 1/2 /W and 99% at 80K, respectively. The dominant noise equivalent temperature differences (NEDT) of typical figure of merit for QDIP thermal imaging module operated under the temperature of 80K, device biases of -0.7 V and integration time of 32ms with infrared optics and two-point temperature correction (T L =R.T. and T H = 200 °C) are 1.065 K (mid-wavelength IR) and 131mK (long-wavelength IR), respectively. Meanwhile, it is worth to note that these are the first confirmation for dual-band detections of FPA from direct InAs quantum dots matrix embedded in GaAs heterostructure. In the future, the dual-band IR QDIP FPA will become one of the important candidates for hyper-spectral detection and thermal imaging fusion application.