Growth and characterization of ZnMgTe/ZnTe layered structures grown by molecular beam epitaxy

Abstract

ZnMgTe/ZnTe layered structures were grown on ZnTe substrates by molecular beam epitaxy, and the crystal structures were characterized using X‐ray diffraction methods. This structure would be the waveguide for various optoelectronic devices. Therefore, the crystal quality of this layered structure would be very crucial for the realization of high performance devices. ZnMgTe is lattice mismatched to ZnTe, and the increase of the ZnMgTe layer thickness or Mg mole fraction ratio would result in the crystal quality deterioration of the layered structure. The critical layer thickness (CLT) was theoretically derived, and various structures with various ZnMgTe layer thickness and Mg mole fraction were grown. The lattice mismatch strain relief and crystal quality of those samples were investigated by means of X‐ray reciprocal space mapping (RSM) and cross sectional transmission electron microscopy (TEM). The dislocation formation and the lattice mismatch relaxation were confirmed for various samples and it was revealed that the calculated CLT values could be used as an appropriate guideline to design the dislocation free and high performance device structures (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Growth of ZnMgTe/ZnTe waveguide structures on ZnTe (001) substrates by molecular beam epitaxy

“…It was found from the RSM data analysis that coherent layer growth was achieved in the region smaller than the CCLT Â 5, and almost coherent growth (mismatch less than 0.2%) was achieved in the region smaller than the CCLT Â 20. On the other hand, relaxed growth (mismatch over 0.2%) was achieved in the region over CCLT Â 20 [9]. Fig.…”

“…where h c is the CLT, b is the size of the Burgers vector (0.43 nm), n is the Poisson's ratio of ZnTe (0.36) [9], a is the angle between the misfit dislocation and its Burgers vector (cos a¼0), f is the lattice mismatch between ZnTe and ZnMgTe, and l is the angle between the slip direction and that direction in the film plane (cos l¼1).…”

“…These defects could affect the device performance [6][7][8]. To predict the critical layer thickness (CLT), an equation proposed by Matthews and Blakeslee was used and the theoretical value was compared with the experimental value [9].…”

(211) oriented ZnTe growth on m‐plane sapphire by MBE

“…1 Introduction II-VI compound semiconductors have attracted much attention for use in various practical devices, including solar cells [1,2], light emitting diode [3,4], UV sensors [5][6][7], electro-optic (EO) devices [8][9][10] and terahertz device applications [11][12][13]. In particular, zinc telluride has a superior permeability and a comparatively high EO effect [14][15][16][17][18] is expected.…”

ZnTe layers on R ‐ and S ‐plane sapphire substrates

“…1 Introduction II-VI compound semiconductors have been widely applied to optoelectronic devices such as solar cells [1,2], X-ray high energy sensors [3,4], waveguides [5][6][7], and terahertz wave devices [8][9][10]. In particular, zinc telluride (ZnTe) has a superior permeability and a comparatively high electro-optic (EO) effect is expected.…”