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Structural characterization of H plasma‐doped ZnO single crystals by Hall measurements and photoluminescence studies
Author(s) -
Anwand Wolfgang,
Brauer Gerhard,
Cowan Thomas E.,
Heera Viton,
Schmidt Heidemarie,
Skorupa Wolfgang,
von Wenckstern Holger,
Brandt Matthias,
Benndorf Gabriele,
Grundmann Marius
Publication year - 2010
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201026311
Subject(s) - photoluminescence , doping , hall effect , materials science , shallow donor , analytical chemistry (journal) , zinc , masking (illustration) , plasma , electrical resistivity and conductivity , optoelectronics , chemistry , metallurgy , art , physics , chromatography , quantum mechanics , electrical engineering , visual arts , engineering
Nominally undoped, hydrothermally grown ZnO single crystals have been investigated prior to and after doping in remote H plasma. Characterizations have been made by temperature‐dependent Hall effect (TDH) and low temperature photoluminescence measurements. The H content before and after the doping has been determined using nuclear reaction analysis and is compared to the density of shallow donors derived from the TDH measurements. The electrical properties of the as‐grown ZnO single crystals are found to differ significantly. This is ascribed to the density ratio of shallow donors and compensating acceptors. PL measurements showed that Al Zn , Ga Zn , and interstitial zinc (Zn i ) are prominent shallow donors in the as‐grown samples. Remote H plasma treatment produced a metallic conducting near‐surface layer thus masking the electrical properties of the bulk. The electrical properties of the investigated samples are very similar after the treatment, independent of the as‐grown state, because the density of shallow donors far exceeds that of compensating acceptors in the affected near‐surface region. The maximum of the broad near‐bandedge emission is found to be located at 3.3595 eV due to the high doping density.