The purpose of this study is to establish a crystal growth technique for quantum wells on InP(110) substrates for spintronics devices operating at 1.55 mu m. This paper reports attempts to optimize growth conditions for InGaAs and InAlAs crystals and their heterostructures on InP(110) and vicinal substrates in molecular beam epitaxy. For crystal growth on InP(110) substrates, the crystal quality of InGaAs/InAlAs quantum wells deteriorated in spite of fabrication in optimized conditions for each of the InGaAs and InAlAs homo-epitaxial layers. A significant number of defects on the ((1) over bar (1) over bar 1) plane were observed in transmission electron microscope (TEM) images; these defects started from the InAlAs buffer and barrier layers. For InP(110) vicinal substrates, we used substrates tilted by 3 degrees from the exact (110) orientation toward (100), (010), (111)A and (111)B poles. We describe the optimized InGaAs/InAlAs quantum wells on InP(110) substrates tilted by 3 degrees toward the (111)B pole. The TEM observation clearly showed the improvement in crystal quality. We also measured absorption spectra of the InGaAs/InAlAs quantum wells. (C) 2012 Elsevier B.V. All rights reserved.