TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The oxidation step employs an elevated temperature of at least 50-2200 degrees C, preferably 120 degrees C. The non-oxide metal-containing particles are deposited on a substrate prior to being subjected to the oxidation step. The non-oxide metal-containing particles are subjected to a pulse of thermal energy having an intensity and duration of time effective for converting the non-oxide metal-containing particles to the metal oxide particles. The pulse has a duration of up to 1 second, preferably 100 mu seconds. The non-oxide metal-containing particles are prepared by microbial synthesis or by abiotic synthesis. The microbial synthesis comprises: subjecting a combination of reaction components to conditions conducive to microbially-mediated formation of non-oxide metal-containing particles, where the combination of reaction components comprises anaerobic microbes, a culture medium suitable for sustaining the anaerobic microbes, a chalcophile metal component comprising at least one type of metal ion, a non-metal component comprising at least one non-metal comprising sulfur, selenium, tellurium or arsenic, and at least one electron donor that provides donatable electrons to the anaerobic microbes during consumption of the electron donor by the anaerobic microbes; and isolating the non-oxide metal-containing particles comprised of at least one of the metal ions and at least one of the non-metals. Preferred Components: The metal oxide particles: possess a size of up to 10 mu , preferably 20 nm; and have a mono-metal oxide composition or a mixed-metal oxide composition containing at least two metals. The metal in the mono-metal oxide or the mixed-metal oxide composition is one of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, hafnium, tantalum, cadmium, molybdenum, tungsten, silver, palladium, platinum, gallium, indium, thallium, germanium, tin, lead, antimony or bismuth. The non-oxide metal-containing particles have a composition comprising metal sulfide, metal selenide, metal telluride, metal nitride, metal phosphide, metal arsenide and/or metal antimonide, where the metal is one of zinc, cadmium, copper, iron, cobalt, nickel, gallium, indium, tin, lead, silver, palladium and/or platinum. The substrate is a functional substrate on which the metal oxide particles remain for integration into an electronic or photonic device. EXAMPLE - Zinc sulfide nanocrystals were synthesized by a nanofermentation technique employing thermoanaerobacter microbes. The zinc sulfide nanocrystals with the tailored size in the scalable process are thermally oxidized to zinc oxide nanocrystals with a slight increase in the average crystallite size. The thermal treatment conditions of the microbially-produced zinc sulfide nanocrystal were argon gas, nitrogen gas and air atmospheres. The zinc sulfide powder was placed in an alumina crucible, loaded into a tube furnace, and then annealed at 600 degrees C with a dwelling time of 2 hours and a ramping rate of 10 degrees C/minute under each atmosphere.