Role of stacking faults as misfit dislocation sources and nonradiative recombination centers in II-VI heterostructures and devices

Abstract

We have investigated the role of stacking faults in high quality ZnSxSe1−x heterostructures and a ZnSxSe1−x/CdxZn1−xSe based II-VI blue-green quantum well laser structure grown on GaAs substrates. We find that these stacking faults, which originate at the epilayer/substrate interface during the initial stages of the growth, act as sources for misfit dislocation formation in the quantum well region of ZnSxSe1−x/CdxZn1−xSe based devices. We have analyzed the formation mechanism of these dislocations. We also show through cathodoluminescence microscopy that these stacking faults act as nonradiative recombination centers which therefore reduce the luminescence of these devices.

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

“…The lattice mismatch is about 4.1 % [3], and such a large lattice would introduce defects at the heterointerface. Device performance of II-VI waveguide structures are very sensitive to defects, and macrodefects (dislocations or stacking faults) as well as microdefects could affect the device performance [4][5][6]. The prediction of the critical layer thickness (CLT) and the formation of defect free structures would be the key issue to realize high performance waveguide structures.…”

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

“…On the other hand, the lattice mismatch between zinc blend MgTe and ZnTe is about 4.1% [5], and such a large lattice mismatch would introduce defects at the ZnMgTe/ZnTe heterointerface, even for Mg composition less than 30%. 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].…”

Characterization of etch pits and correlated defects in ZnSe/(001)GaAs

“…However, densities of as-grown defects are still high for the realization of long-lifetime devices. Many investigations have been carried out with the aim of understanding the mechanism of nucleation of defects and determining methods to eliminate them (Bourret, 1996;Guha et al, 1993;Hua et al, 1994;Kamata and Mitsuhashi, 1994). Transmission electron microscopy (TEM) and the etch pit density (EPD) technique are frequently used for these researchers.…”