Internal Photoemission and Energy Band Discontinuities at Semiconductor Heterojunctions

Haase, Michael Albert

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Description

Title

Internal Photoemission and Energy Band Discontinuities at Semiconductor Heterojunctions

Author(s)

Haase, Michael Albert

Issue Date

1988

Doctoral Committee Chair(s)

Stillman, Gregory E.

Department of Study

Electrical Engineering

Discipline

Electrical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Engineering, Electronics and Electrical

Abstract

• A new technique has been developed to measure the conduction band discontinuities ($\Delta$E$\sb{\rm c})$ at certain semiconductor heterojunctions. The technique involves measuring the spectral response of specially designed p$\sp{+}$N$\sp{-}$ heterojunction photodiodes. Internal photoemission from the valence band of the p$\sp{+}$ layer is observed in these devices and power law fits are used to accurately extract the threshold energy. A simple calculation then gives the size of the conduction band heterobarrier. Subsequent analysis of small barrier lowering effects allows $\Delta$E$\sb{\rm c}$ to be deduced directly, accurately, and reliably.
• This technique has been applied to GaAs-Al$\sb{\rm x}$Ga$\sb{\rm 1-x}$As (x $>$ 0.5) heterojunctions at room temperature and to Ga$\sb{0.47}$In$\sb{0.53}$As-InP heterojunctions over a temperature range of 135 K to 300 K.
• The results and advantages of this technique are compared to previous experimental efforts.

Graduation Semester

1988

Type of Resource

text

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