B.J. HAWDON

Publications (3)4.81 Total impact

• Article: Large observed exciton shifts with electric field in InGaAs/InGaAsP stepped quantum wells

  T. Tutken, B. J. Hawdon, M. Zimmermann, A. Hangleiter, V. Harle, F. Scholz
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  ABSTRACT: We report the experimental realization of asymmetric stepped InGaAs/InGaAsP quantum wells. The structure was designed to optimize the quantum‐confined Stark shift. We have observed a shift of 30 meV in the heavy hole exciton absorption peak over an electric field change of 50 kV/cm. This shift is double that observed for the same structure without the stepped wells.
  Applied Physics Letters 09/1993; · 3.84 Impact Factor
• Article: Direct comparison of InGaAs/InGaAlAs and InGaAs/InGaAsP quantum well modulators

  B.J. Hawdon, T. Tutken, A. Hangleiter, R.W. Glew, J.E.A. Whiteaway
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  ABSTRACT: Using picosecond pump-probe measurements, InGaAs/InGaAlAs and InGaAs/InGaAsP quantum well modulator structures are compared directly. It is found that the short-pulse exciton saturation intensity for the Al-based structure is at least 10 times that for the P-based system. The more efficient carrier sweep-out observed in the Al-based modulator is due to the lower valence-band discontinuity, making it by far the more attractive structure for high-power applications.
  Electronics Letters 05/1993; · 0.96 Impact Factor
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  Available from: archives-ouvertes.fr

  Article: Exciton saturation and field screening in InGaAs/InGaAsP multiple quantum wells

  T. TÜTKEN, B.J. HAWDON, E. SCHEUBLE, M. ZIMMERMANN, P. KÖNIG, A. Hangleiter, V. Härle, F. Scholz
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  ABSTRACT: We performed differential transmission spectroscopy and time resolved pump probe measurements on biased InGaAs/InGaAsP multiple quantum well structures. At low carrier excitation levels we observe a shift in the energy of the excitonic absorption resonance caused by the photogenerated carriers screening the applied electric field within the quantum wells. Increasing the pump power the exciton transmission energy blue shifts until it reaches the zero internal field energy position. For our pump-probe measurements field screening dominates at pump powers lower than 50 W/cm2 while at higher powers exciton saturation becomes dominant. We deduce a saturation intensity of 250 W/cm2.
  http://dx.doi.org/10.1051/jp4:1993550.