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We have found by resistivity measurements and deep‐level transient spectroscopy that four kinds of oxygen‐related shallow donors, OD1–OD4, successively appear around 500 °C in the time region 10–106 min and carbon greatly affects their generation behavior in Czochralski silicon. The formation of OD2 and OD3 donors was enhanced by the presence of carbon, while that of OD1 and OD4 donors was retarded. The OD1 donor is identified as the so‐called thermal donor that consists of several kinds of double donors observed so far by infrared studies. The OD2 donor is a new kind of donor discovered recently by us. OD3 and OD4 donors, which were formed by very prolonged annealing around 500 °C, are suggested to have correlations with so‐called new donors normally generated above 600 °C. The origins of these oxygen‐related donors are discussed in relation to oxygen precipitation.

The surface of Li-doped ZnSe grown on misoriented GaAs(001) substrates by molecular beam epitaxy is studied by means of reflection high energy electron diffraction. Sharp and curved streaky RHEED patterns are observed for all the layers grown on the misoriented substrate towards [110], irrespective of off-angles. No curved pattern, however, is observed on ZnSe layers grown on misoriented GaAs(001) towards [110] with off-angle larger than 5°. We confirmed that the Li-array is surely formed along [110], and that the length of the Li-array is longer than 32Å to be observable as curved streaks. It is also confirmed that the growth rate of Li-doped ZnSe is proportional to the step density, and that the growth rate on the misoriented substrate towards [110] is higher than that on the misoriented substrate towards [110]. The photoluminescence spectra of Li-doped ZnSe layers grown on misoriented GaAs are reported.

This paper demonstrates a unique action of hydrogen on defects and impurities in semiconductors. Hydrogen injected into n-type Si by chemical etching or hydrogen plasma not only pas-sivatcs phosphorus but also electrically activates carbon by forming a H-C complex acting as an electron trap E3 (0.15). A model of the structure and electronic state of the H-C complex is proposed on the basis of available experimental data on the properties of the complex. The diffusion coefficient of isolated hydrogen below 300K is evaluated from its diffusion process to phosphorus after the photoinduccd dissociation of the H-C complex. Some differences in hydrogen diffusion between chemically etched and plasma hydrogenated crystals arc discussed.

In-doped (2 mol%) ZnO films on glass substrate were grown by spray pyrolysis method at 500 °C. Samples were annealed under N2 atmosphere between 100 and 600 °C for 5 min. The X-ray diffraction spectra indicated that the c-axis intensity ratio for a-axis was slightly increased with increasing annealing temperature. This meant that a degree of crystalinity increased with increasing annealing temperature. However, photoluminescence intensity decreased with annealing temperature, indicating that the increased the number of nonradiative recombination centers in the In-doped ZnO films.

CdSe dot generation and dot development on a ZnSe(100) surface are investigated by insitu observation of specular spot intensity (I sp) in a reflection high energy electron diffraction (RHEED) pattern during CdSe growth, using the alternate molecular beam supplying method. From the temporal I sp observation, it is confirmed that CdSe dots are generated immediately after the 1-ML CdSe is formed on 2-ML CdSe wetting layer on ZnSe(100). We also confirmed that the dot growth by Ostwald ripening continues during Cd-beam irradiation, and that the dots sublimate when they are exposed to vacuum at a growth temperature of 250°C. The beam interruption (or growth interruption) strongly affects on the PL peak energy.

We have found with deep level transient spectroscopy (DLTS) measurement two hole traps with a thermal activation energy of 0.20eV and 0.48eV in Se-annealed CuInSe2 grown by a travel heater method (THM). The applications of a reverse and a forward bias under cooling the sample for DLTS cause an increase and a decrease of the trap density of 0.20eV hole trap. It suggests the 0.20eV trap is a metastable defect, the charge state of the trap changes by applying an electric field at low temperature region(

Photoluminescence (PL) and piezoelectric photoacoustic (PPA) measurements are carried out at liquid nitrogen temperature for as-grown and vacuum annealed CuInS2 single crystals grown by a traveling heater method (THM). A new peak, due to S vacancy (VS) defect, is observed in the PPA spectrum after the vacuum annealing. A donor-acceptor pair (DAP) emission band which is due to a recombination between the V donor and In vacancy (VIn) acceptor appears while a DAP (VS donor and Cu vacancy (VCu) acceptor) emission band disappears in the PL spectrum after the vacuum annealing.

We report the details of a post-heating cell developed to obtain high-velocity molecular beams. Zn and Se molecular beams generated from this cell are evaluated by measuring deposition rate by means of a quartz thickness monitor. The observed deposition rates are analyzed by means of a simple model for the operation of an ionization gauge. We found that Zn atoms have a thermal velocity determined by the temperature at the post-heating zone, and that Se molecules are thermally cracked.

Epitaxial layers of ZnSe and ZnS were grown by molecular‐beam epitaxy at temperature as low as 150 °C by using postheated molecular beams generated from elemental materials. To obtain postheated molecular beams as well as to control flux intensity for materials with very high vapor pressure, new types of effusion cells are developed. Experiments under the different temperature and molecular‐beam conditions clarified that the enhancement of the surface migration of Zn atoms is essential to the lowering of the growth temperature.

We have discovered a new family of oxygen‐related double donors [new thermal donors (NTD’s)] generated around 450 °C in phosphorus‐doped Czochralski silicon by combining deep‐level transient spectroscopy with Hall measurements. This new family was well distinguished from the normal family of thermal donors (TD’s) currently studied so far. Our results have shown that both families of thermal donors exhibit qualitatively the same kinetic behavior. Namely, as the annealing time increases, their ionization energy of levels continuously decrease with their densities increasing until the maxima and then become constant with their densities decreasing. However, there are significantly quantitative differences between the both families; NTD’s have shallower levels, considerably smaller generation rates, and higher thermal stability than TD’s. Sufficiently prolonged annealing for more than 105 min around 450 °C or short donor‐killing annealing for 20 min at 650 °C completely annihilates TD’s, leaving only NTD’s, o...

We have studied the effects of low-temperature preannealing and carbon on new donor formation at 650°C in phosphorus-doped Czochralski (CZ) silicon by deep-level transient spectroscopy (DLTS). In not preannealed carbon-lean samples, only a weak continuous DLTS spectrum often reported so far was observed. The intensity of this broad feature became significantly stronger in not preannealed carbon-rich samples. On the contrary, preannealed samples showed no such continuous spectra but two new DLTS peaks arising from shallow donor levels. Carbon enhanced the low-temperature peak, but retarded the high-temperature one. The latter peak is in strong correlation with the rodlike defect.