Growth and characterization of InAsN alloys

The growth of InAsN alloys on InP and InAs substrates by using gas source molecular beam epitaxy (GSMBE) and RF plasma nitrogen source is reported. The samples grown on InP substrates were 3-nm-thick InAsN quantum wells (QWs). The nitrogen composition determined using double crystal X-ray diffractometer (DXRD) is linearly dependent on the nitrogen flow rate. The incorporation of nitrogen decreases the PL emission energy of the QW's. Increase the nitrogen composition by one-percent causes a red-shift energy of 31 meV. The highest nitrogen composition obtained in this study is 5.9%, acid its 10 K PL peak wavelength is as long as 2.6 /spl mu/m (480 meV). The DXRD results also indicate that the satellite peak linewidths of InAsN QWs are narrower than those of InAs QW, which means that the incorporation of nitrogen can sharpen the interfaces of QWs because it results in smaller lattice mismatch. However, increase nitrogen composition also degrades both the DXRD linewidths and the PL intensity. It suggests the existence of the residual strain or immiscibility introduced by the small diameter nitrogen atoms seated on arsenic sites. For InAsN grown on InAs substrates, the incorporation efficiency of nitrogen is much lower than that of InAsN grown on InP substrates. Compressive strain in InAsN on InP substrate could enhance the incorporation of nitrogen.