Hydrogenation of undoped and nitrogen-doped CdTe grown by molecular beam epitaxy

Abstract

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.

Acceptor Neutralisation by Hydrogen in GaN and Wide Band Gap II-VI Materials

“…They noticed that the main luminescence peak increases after hydrogenation whereas, at the same time, the donor-acceptor luminescence decreases. The same type of results has been obtained by Yu et al [16] on nitrogen doped CdTe which had been hydrogenated during the MBE growth; in the hydrogenated samples, the nitrogen-related donor±ac-ceptor pair luminescence is absent whereas other luminescence such as the copper donor±acceptor pair one appears to be enhanced by hydrogen. These results show that at least one of the dopant impurities which contribute to the donor-acceptor pair transitions is neutralised by hydrogen.…”

“…These results have been obtained either in OMVPE grown samples in which hydrogen was non intentional [11,17,18,20,21] or in samples in which hydrogen had been intentionally introduced either during the MBE growth [16] or by exposition to a hydrogen or deuterium radio frequency plasma [19]. In the case of arsenic in ZnSe, deuterium had been also substituted to hydrogen as the carrier gas and in this case, the deuterium related mode has also been reported [21].…”

Nitrogen doping of ZnSe and CdTe epilayers: A comparison of two rf sources

“…[5][6][7] Two rf plasma sources were used in this study of nitrogen doping: the cryogenically cooled CARS-25 Nitrogen is the most promising dopant for p-type ZnSe, and is attractive for CdTe p-type doping, but unwanted compensating centers have limited the maximum achievable carrier densities in both of these material systems. [5][6][7] Two rf plasma sources were used in this study of nitrogen doping: the cryogenically cooled CARS-25 Nitrogen is the most promising dopant for p-type ZnSe, and is attractive for CdTe p-type doping, but unwanted compensating centers have limited the maximum achievable carrier densities in both of these material systems.…”

The use of atomic hydrogen for low temperature oxide removal from HgCdTe

“…10-12 X-ray photoelectron spectroscopy (XPS) characterization experiments were performed in a two-chamber ultrahigh vacuum (UHV) system used for semiconductor processing studies. Epitaxial growth and reflection high energy electron diffraction (RHEED) results were obtained in a molecular beam epitaxy system (MBE) which has been described elsewhere.…”