Photoluminescence of cadmium telluride recrystallized by nanosecond pulsed laser irradiation

Sub-bandgap photoluminescence from as-grown and annealed layers of CdTe

“…Namely, the strained structures of CdTe on Si has been thermally annealed at 400 • C, 500 • C, and 600 • C for 10 s in the work of Neretina et al [15], and the optimum annealing temperature resulting in the highest film quality has been found to be 500 • C. In the presented work we continued to study the effect of longer thermal annealing and higher temperatures on the recombination quality of the CdTe layers. In this article, we present the experimental results on the remarkable improvement of the recombination quality of the CdTe epilayers by post growth thermal annealing.…”

“…From the analysis of the photoluminescence (PL) spectra at 4.2 K of CdTe thin films before and after thermal annealing, the spectrum of the recombination levels can be determined [12]. The latest advances in this area suggest that the effect of stress and lateral defects in CdTe-based epitaxial heterostructures on generation recombination mechanisms could be greatly eliminated by proper growth and thermal annealing [13][14][15][16][17]. Various techniques have been used to achieve this goal in the growth processes of the CdTe layers, namely, molecular beam epitaxy (MBE), metalorganic chemical vapor deposition, hot wall epitaxy, pulsed laser deposition, and electro deposition [18][19][20][21][22].…”

“…Nonetheless, since CdTe/Si structures have a large lattice mismatch ( a/a ≈ 19% at 25 • C) and thermal expansion coefficient difference ( α/α ≈ 46.9% at 25 • C), the interface region inevitably contains strain and dense arrays of dislocations resulting in a deteriorating recombination quality of the CdTe films. Recently, it was established for the CdTe films produced by MBE and VPE on Si (100) substrates that the rapid thermal annealing (RTA) greatly improved the structural quality of CdTe epilayers [15,16].…”

Injection and Optical Spectroscopy of Localized States in II-VI Semiconductor Films

“…The similar peak with energies Ei=1.55 eV and Ei=1.545 eV was registered by authors [92,94,97,99,103]. The common interpretation says that this peak is caused by the electron transition between the conduction band and acceptor ( -A) (a single-charged vacancy Cd V  [94] or other shallow acceptor [92,99]).…”

“…The common interpretation says that this peak is caused by the electron transition between the conduction band and acceptor ( -A) (a single-charged vacancy Cd V  [94] or other shallow acceptor [92,99]). Nevertheless, authors [13,95,103] point out this radiation as a consequence of p resenting donor-acceptor pairs (DAP) where the acceptor is a native defect ( Cd V  ) [13,103] or another uncontrolled shallow impurity [95]. Authors [97] have found the activation energy of corresponding donors and acceptors: 8 meV and 47meV.…”