Skip to main content Accessibility help
×
Home

Radiative Recombination and Carrier Lifetimes in Surface-Free GaAs Homostructures

  • L. M. Smith (a1), D. J. Wolford (a1), R. Venkatasubramanian (a2) and S.K. Ghandhi (a2)

Abstract

We show that the radiative efficiencies and lifetimes of photoexcited carriers in epitaxial GaAs may be enhanced by 3 to 4 orders-of-magnitude by the preparation of n+, doped layers at surface and substrate interfaces. Samples were prepared by Organo-Metallic Vapor Phase Epitaxy (OMVPE), with n-region thicknesses of 3–10 µm, and narrow layers Si-doped to n+ concentrations of 5×1018 cm-3. Time-resolved luminescence in such structures, under both surface and bulk (near-band-edge) excitation conditions, reveal near-edge-excitonic or band-to-band-dominated recombination spectra, with carrier lifetimes ranging from 1.5 nsec at 1.5 K to nearly 1 µsec at room temperature. This is in contrast to the sub-nanosecond lifetimes typical in conventionally prepared bulk GaAs, but is comparable to the best reported for high-purity LPE-prepared GaAs/AlxGa1-xAs double heterostructures. The spatial distributions of photoexcited carriers in these structures are observed to expand by over an order of magnitude during their 1 µsec room temperature lifetime. The expansion is diffusive, with a measured diffusion constant of 14 cm2/sec at 300 K. This corresponds to a room temperature mobility of 525 cm2/Vsec, comparable to previously measured hole mobilities in bulk p-type GaAs of similar purity. These results are clear evidence that the narrow, heavily doped layers effectively “shield” minority carriers from the interfaces, thereby reducing interface recombination.

Copyright

References

Hide All
1 Yablonovitch, E., Sandroff, C.J., Bhat, R., and Gmitter, T., Appl. Phys. Lett. 51, 439 (1987).
2 Liu, D., Zhang, T., LaRue, R.A., Harris, J.S. Jr. and Sigmon, T.W., Appl. Phys. Lett. 53, 1059 (1988).
3 Parkinson, B.A., Heller, A., and Miller, B., Appl. Phys. Lett. 33, 521 (1978).
4 Nelson, R.J., Williams, J.S., Leamy, H.J., Miller, B., Casey, H.C. Jr., Parkinson, B.A., and Heller, A., Appl. Phys. Lett. 36, 76 (1981).
5 Gmitter, T.J., Yablonovitch, E., and Heller, A., J. Electrochem. Soc. 135, 2391 (1988).
6 Ghandhi, S.K., Tyagi, S., and Venkatasubramanian, R., Appl. Phys. Lett. 53, 1308 (1988).
7 Olson, J.M., Ahrenkiel, R.K., Dunlavy, D.J., Keyes, Brian, and Kibbler, A.E., Appl. Phys. Lett. 55, 1208 (1989).
8 Casey, H.C. Jr. and Stern, Frank, J. Appl. Phys. 47, 631 (1976).
9 Nelson, R.J. and Sobers, R.G., J. Appl. Phys. 49, 6103 (1978).
10 Foquet, J.E. and Burnham, R.D., IEEE J. of Quantum Elect., QE–22, 1799 (1986).
11 Dawson, and Woodbridge, Appl. Phys. Lett. 50, 1227 (1984).
12 Matsueda, H. and Hara, K. Appl. Phys. Lett. 55, 362 (1989).
13 Hariz, A., Daniel Dapkus, P., Lee, H.C., Menu, W.P. and DenBaars, S.D., Appl. Phys. Lett. 54, 635 (1989).
14 Iwata, H., Yokoyama, H., Sigumoto, M., Hamao, N. and Onabe, K., 11th Inter. Semicond. Laser Conf. Aug. 29 – Sept. 1, Boston, SPIE, p. 42 (1988).
15 Yablonovitch, E., Bhat, R. and Harbison, J.P., Appl. Phys. Lett. 50, 1197 (1987).
16 Molenkamp, L.W. and van’t Blik, H.F.J., J. Appl. Phys. 64, 4253 (1988).
17 Lasher, G. and Stern, F., Phys. Rev. 133, A553 (1964).
18 Smith, Leigh M., Wolford, D.J., Venkatasubramanian, R. and Ghandhi, S.K.. Electronic Materials Conference, Massachusetts Institute of Technology, Boston, Massachusetts, 1989. Leigh M. Smith, D.J. Wolford, R. Venkatasubramanian and S.K. Ghandhi. Bulletin of the American Physical Society 34, 958 (1989).
19 t’Hooft, G.W., van der Poel, W.A.J.A., Molenkamp, L.W., and Foxon, C.T., in “Excitons in Confined Systems”, Del Sole, R., D’Andrea, A. and Lapiccirella, A., eds., Springer-Verlag, p. 59, 1988.

Related content

Powered by UNSILO

Radiative Recombination and Carrier Lifetimes in Surface-Free GaAs Homostructures

  • L. M. Smith (a1), D. J. Wolford (a1), R. Venkatasubramanian (a2) and S.K. Ghandhi (a2)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.