GaN was grown by molecular beam epitaxy using an rf plasma source. Growth under gallium-rich conditions at 730°C was required to produce high quality layers as indicated by photoluminescence, Hall effect, atomic force microscopy, and x-ray diffraction measurements. Atomic hydrogen has a significant effect for Ga-rich growth, increasing growth rates by as much as a factor of 2.

Atomic hydrogen is demonstrated to effectively clean GaAs substrates for subsequent growth of ZnSe by molecular beam epitaxy. Optical fluorescence microscopy is shown to be a useful technique to image nonradiative defects related to stacking faults. While the density of stacking faults in ZnSe films grown using conventional thermal cleaning is greater than 107 cm−2, stacking fault densities lower than 104 cm−2 are obtained using atomic hydrogen cleaning. Low-temperature photoluminescence spectra of undoped ZnSe are dominated by excitonic transitions for the low defect density samples in contrast to the high level of defect-related emission from high defect density samples.

Atomic hydrogen is shown to be particularly efficacious for the preparation of substrates for subsequent growth of II-VI compounds by molecular beam epitaxy. A commercial thermal cracker was used to produce atomic hydrogen in the molecular beam epitaxy growth chamber for in-situ cleaning. This paper discusses the use of atomic hydrogen for both oxide removal from GaAs prior to ZnSe and CdTe growth, and for low-temperature oxide removal from CdTe and HgCdTe. Reflection high energy electron diffraction, ultra violet fluorescence microscopy, Nomarski interference contrast microscopy, and atomic force microscopy were used to characterize the growths.

The effect of atomic hydrogen during the growth of undoped and nitrogen-doped CdTe by photon-assisted molecular beam epitaxy was investigated. Hydrogen incorporation is enhanced by the presence of nitrogen. Infrared absorption measurements strongly suggest the formation of N–H complexes. Hall measurements indicate that the complexes are donorlike in nature. Hydrogenation radically changes the low temperature photoluminescence in both undoped and nitrogen-doped layers. Exciton-related luminescence is quenched at low temperature. Nitrogen-related donor-acceptor pair luminescence is also absent from N-doped hydrogenated layers, consistent with complex formation. Copper donor–acceptor pair luminescence appears to be enhanced by hydrogen.

Nucleation and growth of GaN under Ga-rich conditions by molecular beam epitaxy using a nitrogen rf plasma source is shown to result in both a smoother GaN surface and a reduced inversion domain content. In addition, preliminary results of the dramatic effect of atomic hydrogen on growth kinetics for Ga-rich growth are presented.