Improved uniformity of self-organized In 0.53Ga 0.47As/In 0.52Al 0.48As quantum wires grown on (7 7 5)B-oriented InP substrate by molecular beam epitaxy

Abstract

Uniformity of self-organized In 0.53Ga 0.47As/In 0.52Al 0.48As quantum wire (QWR) structures grown on (7 7 5)B-oriented InP substrate by molecular beam epitaxy was improved by changing substrate temperature. Both surfaces of In 0.53Ga 0.47As and In 0.52Al 0.48As layers grown at 580°C on the (7 7 5)B InP substrates were corrugated with different periods and amplitudes, which leads to rather poor uniformity of the (7 7 5)B In 0.53Ga 0.47As/In 0.52Al 0.48As QWRs. Surface of an In 0.52Al 0.48As barrier layer grown at 540°C was found to become almost flat. An improved In 0.53Ga 0.47As/In 0.52Al 0.48As QWR structure was fabricated by growing an In 0.53Ga 0.47As QWR layer at 580°C and In 0.52Al 0.48As barrier layers at 540°C. Their full-width at half-maximum (FWHM) values of photoluminescence (PL) observed in the QWRs at 12 K became as small as 19 meV, which is about 40% smaller than that (31 meV) of the previous In 0.53Ga 0.47As/In 0.52Al 0.48As QWRs grown at 580°C. In addition, more improved uniformity (17 meV at 12 K) was realized by using (In 0.53Ga 0.47As) 2(In 0.52Al 0.48As) 2 short period superlattice barriers grown at 540°C. These reduced PL-FWHM values are smaller than those of any InGaAs QWRs emitting 1.1– 1.35 μm PL reported so far.