Ultrahigh Responsivity Of Optically Active, Semiconducting Asymmetric Nano channel Diodes
University of Rochester Rochester United States
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We present our research on the fabrication and optical characterization of novel semiconducting asymmetric nano-channel diodes ANCDs. We focus on optical properties of ANCDs and demonstrate that they can be operated as very sensitive, single-photonlevel, visible-light photodetectors. Our test devices consisted of 1.2-micron-long, roughly 200- to 300-nm-wide channels that were etched in an InGaAsInAlAs quantum-well heterostructure with a two dimensional electron gas layer. The ANCD IV curves were collected by measuring the transport current both in the dark and under 800-nm-wavelength, continuous-wavelight laser illumination. In all of our devices, the impact of the light illumination was very clear, and there was a substantial photocurrent, even for incident optical power as low as 1 nW. The magnitude of the optical responsivity in ANCDs with the conducting nano-channel increased linearly with a decrease in optical power over many orders of magnitude, reaching a value of almost 10,000 AW at 1-nW excitation.
- Electrooptical and Optoelectronic Devices