No abstract

Complementary power field effect transistors (FETs) based on wide bandgap materials not only provide high-voltage switching capability with the reduction of on-resistance and switching losses, but also enable a smart inverter system by the dramatic simplification of external circuits. However, p-channel power FETs with equivalent performance to those of n-channel FETs are not obtained in any wide bandgap material other than diamond. Here we show that a breakdown voltage of more than 1600 V has been obtained in a diamond metal-oxide-semiconductor (MOS) FET with a p-channel based on a two-dimensional hole gas (2DHG). Atomic layer deposited (ALD) Al2O3 induces the 2DHG ubiquitously on a hydrogen-terminated (C-H) diamond surface and also acts as both gate insulator and passivation layer. The high voltage performance is equivalent to that of state-of-the-art SiC planar n-channel FETs and AlGaN/GaN FETs. The drain current density in the on-state is also comparable to that of these two FETs with similar device size and VB.

No abstract

Here, we report a novel method for micropatterning oligonucleotides on the diamond surface via forming amine groups on the diamond surface by nitrogen/hydrogen radical treatment. The covalent bonding of the supporting oligonucleotide and characterization of an immobilized hybridized oligonucleotide with Cy5 modification were investigated by fluorescence microscopy. To investigate the effectiveness of nitrogen/hydrogen radical treatment for amine termination, two types of radical treatment were used: hydrogen/nitrogen radical treatment and pure nitrogen radical treatment. From the results, hydrogen/nitrogen radical treatment produces amine (NH2) termination on the diamond surface. The effect of amine termination was investigated by immobilization of single-stranded DNA via amide bonding between surface NH2 groups and COOH groups terminating the DNA. The immobilized single-stranded DNA (supporting DNA), which has a complementary relationship with the adenosine triphosphate (ATP) aptamer (DNA), hybridizes with the aptamer with attached fluorescence dye. When ATP molecules approach the double-stranded DNA, the aptamer forms a close relationship with the supporting DNA and combines with ATP. ATP detection was effectively carried out by reduction of fluorescence.

Austenitic stainless steels are likely to form oxide scales, which are easy to drol) off to cause some troubles, by contacting with high tempera ture superheated steam in boilers. To solve this problem, it has been known that cold working applied on the surface of austenitic stainless steels is effective to l) revCllt oxidation by high temparature steam. Then the authors trially applied shot blasting to the inner surface of stainless steel tubing fo r cold working. After laboratory tests, stainless tub ings shot blasted all til! illmr surface were set in boilers for practical use. After a year's operation they were removed out and it was observed that there formed a lot of scale all non-worked surface, but that practically no scale was formed all the shot blasted surface. Shot blasting has no adverse effect all the sensitivity of stress corrosion cracking and on the cold bending, thus causing no difJiClllty in p ractical applicatiOllS.