The neutron-irradiation effects on the electrical resistivities of p-LiA1 and p-LiA1 with 48 -54 at. % Li at room temperature are presented. A remarkable decrease of the electrical resistivity is observed in

No abstract

A neutron transmutation doping technique was applied to the high purity n-type germanium with 50 Ω cm (n=5.9×1013/cm3). For a neutron flux density of 5×1011/cm2 s and an irradiation time of 60 min, the doped Ge was converted into p type with 7 Ω cm ( p=3.5×1014/cm3). By neutron irradiation it has been possible to introduce the shallow acceptors resulting from the damage in addition to gallium atoms as acceptors. The recovery of radiation damage was evaluated by the improvements of some electrical properties for various annealing stages. By annealing at 600 °C, a room temperature hole mobility of 2200 cm2/Vs has been achieved at p=6.2×1013/cm3 and ρ=45 Ω cm. And, also, we found that higher mobility holes in p-type Ge play an important role for the weak magnetic field as the lattice atoms recover from the radiation damage. Finally, the direct observation of the recovery of damage was performed by the measurement of channeling effects using a helium ion beam.

Adsorption and desorption of deuterium are studied on the partially oxidized Si͑100͒ surfaces. The partial oxygen coverage causes a decrease in the initial adsorption probability of D atoms. The observed D 2 temperature-programmed-desorption ͑TPD͒ spectra comprise of multiple components depending on the oxygen coverage ( O ). For O ϭ0.1 ML the D 2 TPD spectrum is deconvoluted into four components, each of which has a peak in the temperature region higher than the D 2 TPD peaking at 780 K on the oxygen free surface. The highest TPD component with a peak around 1040 K is attributed to D adatoms on Si dimers backbonded by an oxygen atom. The other components are attributed to D adatoms on the nearest or second nearest sites of the O-backbonded Si dimers. D adatoms on the partially oxidized Si surfaces are abstracted by gaseous H atoms along two different abstraction pathways: one is the pathway along direct abstraction ͑ABS͒ to form HD molecules and the other is the pathway along indirect abstraction via collision-induced-desorption ͑CID͒ of D adatoms to form D 2 molecules. The ABS pathway is less seriously affected by oxygen adatoms. On the other hand, the CID pathway receives a strong influence of oxygen adatoms since the range of surface temperature effective for CID is found to considerably shift to higher surface temperatures with increasing O . Gradual substitution of D adatoms with H atoms during H exposure results in HD desorption along the CID pathway in addition to the ABS one. By employing a modulated beam technique the CID-related HD desorption is directly distinguished from the ABS-related one.

No abstract