Preparation of CdTe Quantum Structures on ZnTe by Hot-Wall Epitaxy

Abstract

The formation of quantum structure of CdTe on ZnTe is investigated. Thin CdTe layers were deposited by hot-wall epitaxy. The thickness of CdTe layer was precisely controlled by alternate deposition of Cd and Te in an auto regulated manner. It is shown that the CdTe quantum structure is appreciably improved by depositing CdTe on thermally annealed ZnTe. We found as experimental result the ripening of CdTe surface.Introduction Much attention has been focused on highly lattice mismatch material systems to fabricate self-organized quantum dots (SQDs). The formation of SQD is known to proceed by the Stranski-Krastanov (S-K) growth mode transition on highly strained epitaxial layers. For II-VI compounds rather extensive work has been done on selenium compound SQDs such as CdSe and ZnCdSe dots on ZnSe [1-3] with wide band gap. A limited number of papers have treated tellurium compound SQDs such as MnTe/CdTe [4] and CdTe/ZnTe [5][6][7] SQDs. Most of II-VI SQDs have been prepared by molecular beam epitaxy (MBE) and works on SQDs formation by hot-wall epitaxy (HWE) is scarce [8]. In the present study we have investigated the improvement of CdTe quantum structures on ZnTe by HWE.

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

“…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]. The growth by vapor phase epitaxy (VPE) has also been considered because of the lower cost, high growth rate, and the capability of producing large area films [3].…”