Photo Gallery of Paul R. Berger, Professor

An optoelectronic integrated circuit (OEIC) photoreceiver consisting of an InGaAs p-i-n photodiode and pi-gate pseudomorphic InGaAs/InAlAs modulation-doped field effect transistor (MODFET). The above circuit with a smaller photodiode was clocked with a 10 GHz bandwidth. The photodetector and transistor were monolithically integrated with two molecular beam epitaxial (MBE) growths, the second being a selective area regrowth, resulting in a planar structure.

A metal-semiconductor-metal (MSM) photodiode showing the entire structure which includes pads for on-wafer microwave probing. A similar MSM photodiode using transparent conductors for the electrodes resulted in a responsivity nearly double to its opaque metal counterpart.

A close-up of the electrode fingers of a metal-semiconductor-metal (MSM) photodiode. The electrodes are 1 micron wide with 1 micron spacings between, realized by standard contact lithography.
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Last updated August 29, 1996