Lateral composition modulation in GaP/InP short-period superlattices grownby solid source molecular beam epitaxy

Transmission electron microscopy (TEM) is employed to investigate the struc tural properties of (GaP)/(InP) short-period superlattices (SPS) grown at t emperatures in the range of 425-490 degreesC by solid source molecular beam epitaxy. TEM results show that lateral composition modulation (LCM) is for med in the SPS layers grown at temperatures above 460 degreesC. Transmissio n electron diffraction results show that CuPt ordering occurs in all sample s. It is shown that the degree of order increases, reaches a maximum at 460 degreesC, and then decreases, as the growth temperature increases. Photolu minescence examination (at 9 K) shows that the samples experience a reducti on in band gap, which is in the range of 55-221 meV, as the growth temperat ure increases. The reduction is attributed to the combined effects of the L CM and CuPt-type ordering. (C) 2001 American Institute of Physics.