LPE growth of crack-free PbSe layers on Si(100) using MBE-Grown PbSe/BaF2CaF2 buffer layers

Abstract

Crack-free PbSe on (100)-oriented Si has been obtained by a combination of liquid phase epitaxy (LPE) and molecular beam epitaxy (MBE) techniques. MBE is employed first to grow a PbSe/BaFJCaF 2 buffer structure on the (100)-oriented Si. A 2.5 ~m thick PbSe layer is then grown by LPE. The LPE-grown PbSe displays excellent surface morphology and is continuous over the entire 8 • 8 mm ~-area of growth. This result is surprising because of the large mismatch in thermal expansion coefficients between PbSe and Si. Previous attempts to grow crack-free PbSe by MBE alone using similar buffer structures on (100)-oriented Si have been unsuccessful. It is speculated that the large concentration of Se vacancies in the LPE-grown PbSe layer may allow dislocation climb along higher order slip planes, providing strain relaxation.

Selective formation of ultrathin PbSe on Ag(111)

“…Epitaxial growth, on the other hand, has been attempted to prepare ultrathin, smooth and thickness controlled PbSe. Various single crystal substrates were used to fabricate PbSe, but islands with large thickness rather than smooth films were obtained, [20,21] which indicates that the interaction between Pb and Se atoms within PbSe is larger than that to substrates. [22] Bilayer-thick PbSe was also prepared in large number of different mismatch layered compounds (PbSe) 1 (MSe 2 ) n , where M represents different transition metals.…”

Growth of Crystallographically Aligned PbSe Films of Controlled Thickness on Amorphous Substrates

“…[27] To obtain high quality crack-free PbSe on BaF 2 /CaF 2 , the buffer layers had to be grown with MBE and the PbSe with liquid phase epitaxy in order to overcome mismatch of thermal expansion coefficients. [27] The growth of single crystals of PbSe was accomplished using chemical solution deposition onto a buffer layer of PbS atop a GaAs substrate. However, the quality of the films produced by this method varied with thickness.…”

“…Molecular beam epitaxy (MBE) on a variety of different substrates has resulted in island growth of PbSe, leading to rough films. [26][27][28] A variety of single crystal substrates that are close to having a lattice match with PbSe were tried, but island formation rather than smooth films were obtained. The substrates were heated to different temperatures to vary the mobility of the deposited atoms, but growth preferentially occurs on the first PbSe that forms rather than the substrate at all of the temperatures investigated.…”

“…[18,[33][34][35] For example, BaF 2 /CaF 2 was used as a buffer layer to grow epitaxial PbSe layers with MBE on Si, but the resulting films cracked, making them unsuitable for device applications. [27] To obtain high quality crack-free PbSe on BaF 2 /CaF 2 , the buffer layers had to be grown with MBE and the PbSe with liquid phase epitaxy in order to overcome mismatch of thermal expansion coefficients. [27] The growth of single crystals of PbSe was accomplished using chemical solution deposition onto a buffer layer of PbS atop a GaAs substrate.…”