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We report on radioluminescence (RL) studies of the wide band gap semiconductors GaP and GaInAsP exposed to tritium gas. All samples were prepared by liquid phase epitaxy. RL tests were performed as a function of tritium pressure, sample temperature, and time, enabling the limiting factors for developing high efficiency visible RL sources to be identified. The studies were complemented by photoluminescence (PL) and cathodoluminescence (CL) measurements. Reduction of surface recombination velocity was shown to be essential for obtaining low threshold CL response and improved PL efficiency. This factor resulted in tritium-activated RL visible to the naked eye. With appropriate materials optimization, these structures should be suitable for developing high efficiency RL devices.

Irradiation of natural isotopic abundance formaldehyde with a narrow linewidth ultraviolet laser has yielded high deuterium enrichments (>600 at 5 Torr, 303 K) at five wavelengths in the range 340 to 355 nm. The temperature and pressure dependence have been measured for both the enrichment and the selectivity, the latter being determined from high resolution spectra of deuterated and natural formaldehyde. In general, for the conditions investigated (293–343 K; 2–26 Torr), both selectivity and enrichment are decreasing functions of temperature and pressure, but in certain cases the selectivity is independent of pressure over a small range. The highest enrichment (1110) was measured at 2 Torr, 293 K, 352.061 nm. The results can be explained in terms of hot bands as well as Doppler broadening and pressure broadening of formaldehyde absorption bands. For all five high enrichment wavelengths, the enrichment is larger than the selectivity at low pressure (