In/sub x/Ga/sub 1-x/As/InP multiquantum well structures grown on [111]B InP substrates

We report the growth and characterisation of In/sub x/Ga/sub 1-x/As/InP quantum well (QW) structures grown on [111]B InP substrates. Photoluminescence (PL) from a range of such structures, grown on substrates with optimum misorientation, show PL linewidths and peak positions equivalent to similar [100] structures. Structural studies, using transmission electron microscopy (TEM) and x-ray diffraction (XRD) show that multiquantum well (MQW) specimens exhibit a high degree of uniformity and a low level of defects. With increasing compressive strain (x>0.53) MQW samples eventually show relaxation, observed through an increase of the XRD peak width and through an increase in linear surface morphological features. Room temperature photocurrent measurements on strained p-i(MQW)-n diode structures show a strong excitonic blue shift, demonstrating excellent potential for low voltage, long wavelength, optical modulators.