Abstract: In the present invention, there is provided semiconductor devices such as a Schottky UV photodetector fabricated on n-type ZnO and MgxZn1-xO epitaxial films. The ZnO and MgxZn1-xO films are grown on R-plane sapphire substrates and the Schottky diodes are fabricated on the ZnO and MgxZn1-xO 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.

Abstract: In the present invention, there are provided self-assembled ZnO nanotips grown on relatively low temperatures on various substrates by metalorganic chemical vapor deposition (MOCVD). The ZnO nanotips are made at relatively low temperatures, giving ZnO a unique advantage over other wide bandgap semiconductors such as GaN and SiC. The nanotips have controlled uniform size, distribution and orientation. These ZnO nanotips are of single crystal quality, show n-type conductivity and have good optical properties. Selective growth of ZnO nanotips also has been realized on patterned (100) silicon on r-sapphire (SOS), and amorphous SiO2 on r-sapphire substrates. Self-assembled ZnO nanotips can also be selectively grown on patterned layers or islands made of a semiconductor, an insulator or a metal deposited on R-plane (01{overscore (1)}2) Al2O3 substrates as long as the ZnO grows in a columnar stucture along the c-axis [0001] of ZnO on these materials.

Abstract: The present invention provides the multifunctional biological and biochemical sensor technology based on ZnO nanostructures. The ZnO nanotips serve as strong DNA or protein molecule binding sites to enhance the immobilization. Patterned ZnO nanotips are used to provide conductivity-based biosensors. Patterned ZnO nanotips are also used as the gate for field-effect transistor (FET) type sensors. Patterned ZnO nanotips are integrated with SAW or BAW based biosensors. These ZnO nanotip based devices operate in multimodal operation combining electrical, acoustic and optical sensing mechanisms. The multifunctional biosensors can be arrayed and combined into one biochip, which will enhance the sensitivity and accuracy of biological and biochemical detection due to strong immobilization and multimodal operation capability. Such biological and biochemical sensor technology are useful in detection of RNA-DNA, DNA-DNA, protein-protein, protein-DNA and protein-small molecules interaction.

Abstract: In the present invention, there is provided semiconductor devices such as a Schottky UV photodetector fabricated on n-type ZnO and MgxZn1-xO epitaxial films. The ZnO and MgxZn1-xO films are grown on R-plane sapphire substrates and the Schottky diodes are fabricated on the ZnO and MgxZn1-xO 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.

Abstract: The present invention provides magnesium zinc oxide (MgxZn1-xO) as a new piezoelectric material, which is formed by alloying ZnO and MgO. MgxZn1-xO allows for flexibility in thin film SAW and BAW device design, as its piezoelectric properties can be tailored by controlling the Mg content, as well as by using MgxZn1-xO/ZnO multilayer structures. To experimentally prove it, the MgxZn1-xO (x≦0.35) thin films are grown on r-plane sapphire substrates at a temperature in the range of 400° C.-500° C. by metalorganic chemical vapor deposition. MgxZn1-xO films with Mg mole percent up to 0.35 have epitaxial quality and wurtzite crystal structure. The SAW properties, including velocity dispersion and piezoelectric coupling, are characterized and concluded that the acoustic velocity increases, whereas the piezoelectric coupling decreases with increasing Mg mole percent in piezoelectric MgxZn1-xO films.

Abstract: In the present invention, there are provided self-assembled ZnO nanotips grown on relatively low temperatures on various substrates by metalorganic chemical vapor deposition (MOCVD). The ZnO nanotips are made at relatively low temperatures, giving ZnO a unique advantage over other wide bandgap semiconductors such as GaN and SiC. The nanotips have controlled uniform size, distribution and orientation. These ZnO nanotips are of single crystal quality, show n-type conductivity and have good optical properties. Selective growth of ZnO nanotips also has been realized on patterned (100) silicon on r-sapphire (SOS), and amorphous SiO2 on r-sapphire substrates. Self-assembled ZnO nanotips can also be selectively grown on patterned layers or islands made of a semiconductor, an insulator or a metal deposited on R-plane (01{overscore (1)}2) Al2O3 substrates as long as the ZnO grows in a columnar stucture along the c-axis [0001] of ZnO on these materials.

Abstract: The present invention provides magnesium zinc oxide (MgxZn1-xO) as a new piezoelectric material, which is formed by alloying ZnO and MgO. MgxZn1-xO allows for flexibility in thin film SAW and BAW device design, as its piezoelectric properties can be tailored by controlling the Mg content, as well as by using MgxZn1-xO/ZnO multilayer structures. To experimentally prove it, the MgxZn1-xO (x≦0.35) thin films are grown on r-plane sapphire substrates at a temperature in the range of 400° C.-500° C. by metalorganic chemical vapor deposition. MgxZn1-xO films with Mg mole percent up to 0.35 have epitaxial quality and wurtzite crystal structure. The SAW properties, including velocity dispersion and piezoelectric coupling, are characterized and concluded that the acoustic velocity increases, whereas the piezoelectric coupling decreases with increasing Mg mole percent in piezoelectric MgxZn1-xO films.

Abstract: In the present invention, there is provided semiconductor devices such as a Schottky UV photodetector fabricated on n-type ZnO and MgxZn1-xO epitaxial films. The ZnO and MgxZn1-xO films are grown on R-plane sapphire substrates and the Schottky diodes are fabricated on the ZnO and MgxZn1-xO 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.