Title :
Mechanisms of laser-induced defect formation and in doping in CdTe crystals
Author :
Gnatyuk, V.A. ; Aoki, T. ; Hatanaka, Y.
Author_Institution :
Res. Inst. of Electron., Shizuoka Univ., Hamamatsu, Ukraine
Abstract :
The laser-stimulated modification of the crystalline and point defect structure of the surface layer of CdTe crystals was studied and laser-induced doping was performed to form electrical barriers in the surface region of samples. The results of comprehensive investigations of time-resolved optical reflectivity, atomic force microscopy, reflection of high-energy electron diffraction, current-voltage characteristics, exciton photoluminescence in (111)B oriented CdTe crystals subjected to irradiation with nanosecond KrF excimer laser pulses have been discussed. The peculiarities of pulsed-laser-induced melting and following crystallization of the CdTe surface depending on laser energy density have been analyzed. The melting and ablation thresholds were determined as 50 mJ/cm2 and 145 mJ/cm2, respectively. Using laser irradiation of CdTe crystals pre-coated with an indium dopant film, it was possible to suppress the self-compensation mechanism and fabricate the CdTe-based diodes promising for nuclear radiation detectors. The mechanisms of laser-induced defect formation and doping have been discussed.
Keywords :
atomic force microscopy; crystal orientation; crystallisation; doping profiles; excimer lasers; excitons; high energy electron diffraction; indium; laser beam annealing; light reflection; melting; photoluminescence; point defects; radiation detection; reflection high energy electron diffraction; reflectivity; semiconductor counters; surface structure; (111)B oriented CdTe crystals; CdTe-based diodes; ablation threshold; atomic force microscopy; crystalline structure; crystallization; current-voltage characteristics; electrical barriers; exciton photoluminescence; indium dopant film; laser annealing; laser energy density; laser-induced defect formation; laser-induced doping; laser-stimulated modification; nanosecond KrF excimer laser pulse irradiation; nuclear radiation detector; p-n junctions; point defect structure; pulsed-laser-induced melting; reflection of high-energy electron diffraction; self-compensation mechanism; semiconductor defects; surface layer; surface structure; time-resolved optical reflectivity; Atom optics; Atomic force microscopy; Crystallization; Doping; Electron optics; Laser ablation; Optical films; Optical microscopy; Optical pulses; Surface emitting lasers; Doping; laser annealing; p-n junctions; radiation detectors; semiconductor defects;
Journal_Title :
Nuclear Science, IEEE Transactions on
DOI :
10.1109/TNS.2004.836068
