No abstract

ZnO nanowires have been synthesized on porous silicon substrates with different porosities via the vapour-liquid-solid method. The texture coefficient analysed from the XRD spectra indicates that the nanowires are more highly orientated on the appropriate porosity of porous silicon substrate than on the smooth surface of silicon. The Raman spectrum reveals the high quality of the ZnO nanowires. From the temperature-dependent photoluminescence spectra, we deduced the activation energies of free and bound excitons.

Two new isotypic anhydrous borophosphates, KMBP(2)O(8) (M = Sr, Ba), have been prepared under high temperature solution growth (HTSG). Investigation of single-crystal X-ray diffraction shows that they crystallize in noncentrosymmetric space group I42d with the following lattice parameters: a = 7.1095(18), c = 13.882(5)A for KSrBP(2)O(8) and a = 7.202(2), c = 14.300(6)A for KBaBP(2)O(8). The fundamental building block (FBB) of title borophosphates with B:P ratio = 1:2 is 12square:<12square> (symbol square represents BO(4) and PO(4) tetrahedra). The FBBs are further interlocked together to form the final 3D diamond-like architecture. Second-harmonic generation (SHG) on powder samples has been measured using Kurtz and Perry technique, which indicates that they are phase-matchable materials, and their SHG coefficients are measured to be about 1/5 (for KSrBP(2)O(8)) and 1/3 (for KBaBP(2)O(8)) times as large as that of KDP.

No abstract

No abstract

No abstract

We report a very high performance lOOnm gate length CMOS transistor structure operating at 1.2-1 SV. These transistors are incorporated in a 180nm logic technology generation. Various process enhancements are incorporated to significantly improve transistor current drive capability relative to the results published in [I]. Unique transistor features responsible for achieving high performance are described. NMOS and PMOS devices demonstrate drive current of 1.04 mA/pm and 0.46 mA/pm respectively at 1.5V and 3nA/pm IOFF. These are the best drive currents reported to date at fixed IOFF. They represents 10% drive current improvement for both NMOS and PMOS devices relative to the results published in Ref.[l] without any change in gate-oxide thickness. High performance is demonstrated down to 1.2V. Inverter delay of less than 10 psec is reported at 1.5V at very moderate IOFF values.

Basal plane stacking faults (BSFs) with density of ∼1 × 106 cm−1 are identified as the dominant defect in the annealed ZnO thin films grown on c-plane sapphire by atomic layer deposition. The dominant peak centered at 3.321 eV in low-temperature photoluminescence measurements is attributed to the emission from the BSFs. The emission mechanism is considered to be the confined indirect excitons in the region of quantum-well-like structure formed by the BSFs. The observed energy shift of 19 meV with respect to the BSF-bounded exciton at low temperature may be caused by the localization effect associated with the coupling between BSF quantum wells.