Abstract
A series of strained InxGa1−xAs/AlAs multiple quantum well p–i–n diodes with x varyingfrom 0·06 to 0·15 has been investigated. High resolution X-ray diffractometry was used to determine the In concentration, the well width, and the degree of strain relaxation for the higher In samples. Simulations enabled information concerning the thickness uniformity and interfacial abruptness to be obtained. Reciprocal space mapping permitted direct measurement of residual strain and tilt in the layers. Photocurrent spectroscopy for both pseudomorphic and partially relaxed samples showed strong room temperature excitonic features and a strong quantum confined Stark effect under an applied electric field, attributed to the confining potential of the AlAs barriers. The excitonic spectral positions were in good agreement with band structure calculations made using the structural parameters determined using X-ray diffractometry.
MST/3248
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