A ten-stacked self-assembled InAs/GaAs quantum-dot infrared photodetector operated in the 2.5-7 m range by photovoltaic and photoconductive mixed-mode near-room-temperature operation ͑у250 K͒ was demonstrated. The specific peak detectivity D* is 2.4ϫ10 8 cm Hz 1/2 /W at 250 K. The use of high-band-gap Al 0.3 Ga 0.7 As barriers at both sides of the InAs quantum-dot structure and the long carrier recombination time are the key factors responsible for its near-room-temperature operation.

In this letter, the effect of extraordinary transmission of periodic metal hole arrays is directly integrated into the quantum dot infrared photodetector with broadband response. It is found that the detector response is strongly modulated by the extraordinary transmission from the excitation of surface plasmon.

No abstract

The data obtained in the present study highlight the importance of local lymphocytes and anti-angiogenesis for influencing the antitumor activity of these three IL-12 family cytokines and suggest that IL-12 is the best candidate for treating HCC.

We report on analysis and comparison of the dark current characteristics between InAs p-n and p-i-n diodes at the temperature range from 30 to 300 K. The situation that the dark current is completely due to the bulk instead of the surface leakage is made sure by passivation treatment. The experimental results agree well with a tunnel diode model in which the p-n and p-i-n diodes are described, respectively, with a linear electrical field and a constant electrical field. The diffusion current in our diodes is dominated by the electron diffusion in the p-type material. Through this model and detailed analysis, we conclude that the tunneling current can be suppressed with an intrinsic layer and a low n-type doping density while the diffusion current can be decreased with a high p-type doping density. The advantage of the p-i-n structure is not only to cut down the tunneling current but also to increase the uniformity. In terms of this model, a new p-i-n diode is designed to dramatically increase its zero-bias resistance area product and improve the detector performance.