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Rutgers, The State University of New Jersey

Corning Applied Technologies Corporation

Shaohua Liang

Yicheng Lu

Yi-Qun Li

Paul H Shen

Michael Wraback

Hua Jiang

Chandrasekhar R Gorla

Nuri William Emanetoglu

Sriram Muthukumar

Jian Zhong

Wei Hu

Haifeng Sheng

Vladimir Fuflyigin

Jiankang Huang

In the present invention, there is provided semiconductor devices such as a Schottky UV photodetector fabricated on n-type ZnO and MgZnO epitaxial films. The ZnO and MgZnO films are grown on R-plane sapphire substrates and the Schottky diodes are fabricated on the ZnO and MgZnO films using silver and aluminum as Schottky and ohmic contact metals, respectively. The Schottky diodes have circular patterns, where the inner circle is the Schottky contact, and the outside ring is the ohmic contact. Ag Schottky contact patterns are fabricated using standard liftoff techniques, while the Al ohmic contact patterns are formed using wet chemical etching. These detectors show low frequency photoresponsivity, high speed photoresponse, lower leakage current and low noise performance as compared to their photoconductive counterparts. This invention is also applicable to optical modulators, Metal Semiconductor Field Effect Transistors (MESFETs) and more.

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A ferroelectric layer is deposited or in close proximity to a ferromagnetic ferrite layer to make a microwave substrate on which conductors can be deposited or placed to make devices. The permittivity of the ferroelectric layer can be changed by applying a voltage and the permeability of the ferromagnetic layer can be changed with a magnetic field. This makes it possible to tune the device characteristics with two different effects taking best advantage of the capabilities of each. A material example is ferromagnetic yttrium-iron-garnet on which is deposited a thin film of ferroelectric barium strontium titanate. To minimize losses, the ferroelectric film should be high quality, but practical yttrium-iron-garnet substrates are polycrystalline so that the use of buffer layers is desirable. At least two methods can be used to deposit the ferroelectric film, pulsed laser deposition and metal-organic chemical liquid deposition. A variety of dual tunable microwave devices can be made with this substrate, including by way of example only, phase shifters, frequency filters, and resonators.

Dual-tuning microwave devices using ferroelectric/ferrite layers

A high contrast ultrahigh speed optically-addressed ultraviolet light modulator exploits the optical anisotropy in a ZnO film epitaxially grown on sapphire. This device, which could also be realized in a ZnO bulk crystal or similar wide bandgap material, achieves both high contrast and high speed by exploiting the anisotropic bleaching of the anisotropic absorption and concomitant ultrafast polarization rotation near the lowest exciton resonances produced by femtosecond ultraviolet pulses. The resultant modulation in a preferred embodiment is characterized by a contrast ratio of 70:1, corresponding to a dynamic polarization rotation of 12&deg;, and decays to a quasi-equilibrium value within 100 ps.

High contrast, ultrafast optically-addressed ultraviolet light modulator based upon optical anisotropy

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Somerset, NJ, United States of America

Shaohua Liang