Comparison of InGaAs/InAlAs electroabsorption modulator structures on (100) and (111) InP substrates

The MBE growth and properties of InGaAs/InAlAs heterostructures on vicinal (111)B InP substrates have been investigated. Electroabsorption modulator p in MQW heterostructures were grown on both (100) and vicinal (111)B InP sub strates, pin diodes were processed and their photocurrent spectra at 300 K were compared. The spectra of (100) structures exhibited many intense excit onic transitions and applied reverse bias resulted to strong red shift of t he absorption edge. The photocurrent spectra of similar (111) structures, h owever, appeared rather featureless with less abrupt absorption edge. These results on (111) are related to crystal disorder and quantum well variatio ns resulting from InAlAs surface step-bunching and InGaAs, InAlAs compositi onal modulations. (C) 1999 Elsevier Science S.A. All rights reserved.