GROWTH AND CHARACTERIZATION OF GAINP UNICOMPOSITIONAL DISORDER-ORDER-DISORDER QUANTUM-WELLS

Metalorganic vapor phase epitaxy (MOVPE) is used to grow unicompositio nal quantum-well (QW) structures, in which the QW and barrier layers a re composed of ordered and disordered GaInP, respectively. Transmissio n electron dark-field micrographs reveal abrupt interfaces between hig hly ordered QWs and disordered barriers, with no evidence of defect fo rmation. Low-temperature photoluminescence from the structures exhibit s relatively broad emission peaks, with emission energy increasing wit h decreasing QW thickness. The dependence of emission energy on well t hickness can be described by a finite square well model only when a ty pe-II band alignment is taken for the heterostructure, in which the co nduction band edge of the ordered GaInP QW lies about 135-150 meV belo w that of the disordered barrier material. These results demonstrate a high degree of control over the ordering process in MOVPE, such that quantum size effects can be realized solely through disorder-order phe nomena. Further, the data provide strong support for a type-II (spatia lly indirect) recombination transition between ordered and disordered GaInP.