Effective barriers induced by confined carriers in space charge spectroscopy of Si/Ge quantum wells
✍ Scribed by K. Schmalz; H. Rücker; H.P. Zeindl; I.N. Yassievich
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 162 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0749-6036
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✦ Synopsis
Results are presented concerning the characterization of (\mathrm{p}-\mathrm{Si}^{2} / \mathrm{Si}{\mathbf{1}-\mathrm{x}} \mathrm{Ge}{\mathbf{x}} / \mathrm{Si}) quantum wells (QW) by space charge spectroscopy. Analysis of potential barriers at the QW cnables us to determine the valence band offsct from such measurements. Admittance spectroscopy data of QWs with (30 \mathrm{~nm}) undoped spacers, acceptor concentration (N_{A}) of about (10^{17} \mathrm{~cm}^{-3}) in the cap and huffer layers, (x=0.25) and a (Q W) thickness in the range from 1 to (5 \mathrm{~nm}) are in fair agreement with the proposed theoretical model. A decrease of the effective potential barriers due to hole tunneling via shallow acceptor states in the barrier is experimentally confirmed for (5 \mathrm{~nm}) QW structures without spacers.