Novel Heterodimensional Sensors

The sensing element is the heart of a sensor. A generic requirement for any sensor is that it only responds to the particular stimulus since all other stimuli are considered noise. The basic physics of the operation of a sensor thus determines the limitof its sensitivity. Here we build upon a family of proposed light sensors in which sensor noise is substantially reduced by altering the nature of current transport. This is done by 1) confining the electrons in a reduced dimensional regime such as aquantum well or wire, and 2) producing a contact of a different dimension to this electron cloud. These hetero-dimensional devices substantially affect current transport. We will fabricate and test detectors for operation in the near infrared (NIR)regime that will surpass present technology in terms of dark current, responsitivity, and speed. We will fabricate and test Photodiodes, Photoconductors, Schottky diodes, and HEMTs on the same monolithic substrate demonstrating the feasibility of thefabrication of all the elements necessary for a photoreceiver, or an imaging array. We then apply this design strategy to a different material system that is especially suitable for operation in 1300 and 1550 nm windows for use in long haul fiber opticcommunication networks. As result of this work, devices that exceed present technology in terms of noise performance, sensitivity, and speed will be fabricated and tested. Initial concentration is on 700-900nm ranged followed by work in 1300-1550nmrange. Applications of these devices are in a variety of areas, but the most promising are the following:1. Receivers for Fast Ethernet 2. Receivers for Long Haul Communication 3. Wavelength Division Multiplexing receivers. 4. Near Infrared MedicalImaging