Sains Malaysiana 29: 145-161 (2000)                                                                           Sains Fizis dan Gunaan /

Physical and Applied Sciences

Modelling of Stark Effect in InAs-AlGaSb

Multi-Quantum Wells

Geri Kibe AK Gopir

Faculty of Life Sciences

Universiti Kebangsaan Malaysia

43600 UKM Bangi

Selangor D.E. Malaysia

ABSTRACT

The Stark effectina (20)InAs­(6)As-(6)Al_0.1Ga_0.9 Sb multi-quantum well structure was theoretically modelled using the electric-field-perturbed formulation of the empirical pseudopotential method. An external electric field of up to 4.0 x 1()5 V cm-! was applied along the axis of the multi-quantum well structure and its effect on the energy level, localisation and optical transition of the lowest electron and hole states were investigated. The perturbation pro­duced Wannier-Stark localisation and a red Stark shift for this type II semiconductor heterostructure. The calculated optical gap decreased down to 10 meV with the corresponding principal momentum matrix elements, along x polarisation, remain basically constant  at  a.u.(atomic unit). This property makes the III-V semiconductor heterostructure poten­tially attractive for use as a field-tunable device in the infrared spectra of  10-100µm.

ABSTRAK

Kesan Stark dalam suatu struktur telaga kuantum berbilang (20)InAs­(6)As-(6)Al_0.1 Ga_0.9 Sb telah dikaji secara teori berdasarkan rumusan usikan medan elektrik bagi kaedah pseudokeupayaan empirik. Satu medan elektrik luaran sehingga 4.0 x 10⁵ V cm^-1 telah dikenakan di sepanjang paksi struktur telaga kuantum berbilang dan kesannya ke atas aras tenaga, pelokalan dan peralihan optik bagi keadaan-keadaan elektron dan lohong yang terendah telah diselidiki. Usikan ini telah menghasilkan pelokalan Wannier-Stark dan satu anjakan Stark merah bagi heterostruktur semikonduktor jenis II ini. Jurang optik kiraan telah turun sehingga 10 meV dengan unsur matriks momentum utama yang sepadan, di sepanjang pengkutuban x, agak malar pada  (unit atom). Sifat ini menjadikan heterostruktur semikonduktor III-V ini berpotensi untuk digunakan sebagai peranti tertala medan bagi spektrum inframerah pada 10-100 µm.

RUJUKAN/REFERENCES

Austin, E. J. & Jaros, M. 1987. Electronic structure and transport properties of GaAs­GaAAs superlattices in high perpendicular electric fields. J. Appl. Phys. 62: 558-564.

Bastard, G., Mendez, E. E., Chang, L. L. & Esaki, L. 1983. Variational calculations on a quantum well in an electric field. Phys. Rev. B28: 3241-3245.

Bleuse, J., Bastard, G. & Voisin, P.1988. Electric-field-induced localization and oscillatory electro-optical properties of semiconductor superlattices. Phys. Rev. Lett. 60: 220-223.

Dignam, M. M. & Sipe, J. E. 1991. Exciton Stark ladder in semiconductor superlattices. Phys. Rev. B43: 4097-4112.

Grimmeiss, H. G., Nagesh, V., Presting, H., Kibbel, H. & Kasper, E. 1992. Optical studies of short-period Si/Ge superlattices by photocapacitance. Phys. Rev. B45: 1236-1239.

Hagon, J. P. & Jaros, M. 1990. Stark shifts in GaAs-Ga₁._xAl_xAs finite-length superlattices. Phys. Rev. B41: 2900-2905.

Hagon, J. P., Jaros, M. & Herbert, D. C. 1989. Effect of band structure on Stark shifts in GaAs quantum wells. Phys. Rev. B40: 6420-6423.

Hagon, J. P., Turton, R. J., Miloszewski, A. T., Elfardag, G. S. M. & Jaros, M. 1994. The effect of an electric field on optical spectra and transmission in Si-Si1-xGex quantum well structures.  Superlattices and microstructures 16: 125-131.

Hamaguchi, C., Yamaguchi, M., Morifuji, M., Kubo, H., Taniguchi, K., Gmachi, C. & Gornik, E. 1994. Wannier-Stark effect in superlattices. Semicond. Sci. Technol. 9: 1994-1998.

Harrison, P. 1991. Electronic and Optical Properties of Semiconductor Superlattices. Ph. D. Thesis. University of Newcastle Upon Tyne, U. K.

Jaros, M., Beavis, A.W., Hagon, J. P., Turton, R. J., Miloszewski, A. & Wong, K. B. 1992. Quantitative theory of optical properties of Si-Ge heterostructures. Thin Solid Films. 222: 205-208.

Jaros, M. & Wong, K. B. 1984. New electron states in GaAs-Ga_xA_1-x.As superlattice. J. Phys. C: Solid State Phys. 17: L765-L769.

Jaros, M., Wong, K. B. & Gell, M. A. 1985. Electronic structure of GaAs-Ga_xA1_1-xAs,. As quantum well and sawtooth superlattices. Phys. Rev. B31: 1205-1207.

Mendez, E. E., Agullo-Rueda, F. & Hong, J. M. 1988. Stark localization in GaAs­GaAIAs superlattices under an electric field. Phys. Rev. Let. 60: 2426-2429.

Miller, D. A. B., Chemla, D. S., Damen, T. C., Gossard, A. C., Wiegmann, W., Wood, T. H. & Burrus, A. C. 1985. Electric field dependence of optical properties near the band gap of quantum-well structures. Phys. Rev. B32: 1043-1058.

Morifuji, M., Yamaguchi, M., Taniguchi, K. & Hamaguchi, C. 1994. Electric-field ­induced Q-X mixing between Stark ladders in short-period GaAs/AIAssuperlattices. Phys. Rev. B50: 8722-8726.

Satzke, K., Weiser, G., Stolz, W. & Ploog, K. 1991. Optical study of the electronic states of In_0.53Ga_0.47As/In_0.52AI_0.48As quantum wells in high electric fields. Phys. Rev. B43: 2263-2271.

Sze, S. M., 1990. Ed. High Speed Semiconductor Devices. New York: Wiley­ Interscience.

Van de Walle, C. G. 1989. Band lineups and deformation potentials in the model­solid theory. Phys. Rev. B39: 1871-1883.

Wong, K. B., Gopir, G. K. A., Hagon, J. P. & Jaros, M. 1994. Absorption coefficient and electric-field-induced localization in InAs-AIGaSb multi-quantum well struc­tures. Semicond. Sci. Technol. 9: 2210-2216.

Yamaguchi, M., Nagasawa, H., Morifuji, M., Taniguchi, K., Hamaguchi, c., Gmachi, C. & Gornik, E. 1994. Stark-ladder transition in type-II (GaAs)₈/(AIAs)₈ superlattice. Semicond. Sci. Technol. 9: 1810-1814.

Yamanaka, K., Fukunaga, T., Tsukuda, N., Kobayashi, K. L. I. & Ishii, M. 1986. Photocurrent spectroscopy in GaAs/AlGaAs multiple quantum wells under a high electric field perpendicular to the heterointerface. App. Phys. Lett. 48: 840-842.