InSb quantum dots and quantum rings in a narrow-gap InAsSbP matrix

Abstract

We report a study of InSb quantum dots and quantum rings grown on InAs(100) substrate by LPE-MOVPE combine method. Characterization of InSb/InAs(Sb,P) quantum dots was performed using atomic force microscopy and transmission electron microscopy. The bimodal growth of uncapped InSb quantum dots was observed in the temperature range T=420-450 0 C. The low-density (5×10 8 cm -2 ) large quantum dots with dimensions of 12-14 nm in height and 45-50 nm in diameter are appeared at 445 0 C, whereas high-density (1×10 10 cm -2 ) dislocation-free small quantum dots with dimensions of 3-5 nm in height and 11-13 nm in diameter were obtained at 430 0 C. Capping of the InSb quantum dots by binary InAs or InAsSbP epilayers lattice-matched with InAs substrate was performed using MOVPE method. Tunnelrelated behavior in a forward curve of I-V characteristics was observed in heterostructures with buried InSb quantum dots inserted in InAs p-n junction. Evolution of electroluminescence spectra on driving current at negative bias and suppression of negative luminescence from buried InSb/InAs quantum dots were found out in the spectral range 3-4 μm at 300 K. Deposition from the InSb melt over the InAsSb 0.05 P 0.10 capping layer resulted in the formation of InSb quantum rings with outer and inner diameters about 20-30 nm and 15-18 nm respectively. Surface density of the quantum rings of 2.6×10 10 cm -2 was reached at 430 0 C.

Tunability of absorption threshold frequencies and Stark shift in the InSb narrow gap spherical quantum layer

“…We have compared our results with the experimental results obtained by Moiseev et al in [18], where the electroluminescence and photoluminescence spectra of InSb/InAs QDs are observed. In figure 5 the comparison of the calculated threshold energies for InSb QD with the radius of 6.5 nm and for SQL with the inner radius of 2 nm and outer radius of 6.5 nm with the threshold energy obtained in [18] is presented. A difference of about 18% between the experimental and calculated threshold energies for QD (peaks 1 and 2) is caused by the use of the infinitely high potential barriers model in our calculations.…”

“…This effect is directly caused by the coupling of the states and cannot be observed in the framework of remote levels approach. Finally, it is obvious from the figure that the dependences of the Stark shift on inner radius as well as on electric field strength is stronger for the case of nonparabolic dispersion because of the higher localization degree in the 1s and 1p states and larger value of matrix element (18).…”

“…The dependences of the 1s and 1p states' Stark shift on the inner radius of SQL and dimensionless electric field strength (η = eFa B /E R ) are presented in figure 7. The obvious increase of | E| with the increase of R 1 in figure 7(a) is caused by the increase of the overlap integral in (18) due to the increasing of quantization degree in SQL. On the other hand, the Stark shifts of 1s and 1p states have opposite signs and the same absolute values ( E 1s = | E 1s | = − E 1p ) as follows from (17).…”

Type II heterostructures with InSb quantum dots inserted into p-n InAs(Sb,P) junction

“…We suppose that the PL peak at 3.82 μm can be ascribed to localized states caused by presence of the InSb QDs at the p-n inAs heterointerface. 19 At low temperatures, the spectra obtained at both forward and reverse bias demonstrated positive luminescence only (Fig. 11).…”

Growth and characterization of cooperative quantum dot chains in quaternary InAsSbP material system

“…Actually, the well established LPE growth technique has been improved and successfully employed for the growth of quantum well heterostructure lasers, 22 InAsSbP quaternary composition lens-shape and ellipsoidal QDs, [23][24][25] quantum rings 26,27 and QD molecules in the form of InAsSb-QD/InAsP-leaves cooperative structures (so-called nano-camomiles). 28,29 Note, that all these nanostructure were grown on industrial InAs(100) substrates' epi-ready surface.…”