The growth of low band-gap InAs on (111)B GaAs substrates
The use of low band-gap materials is of interest for a number of photovoltaic and optoelectronic applications, such as bottom cells of optimized multijunction solar cell designs, long wavelength light sources, detectors, and thermophotovoltaics. However, low band-gap materials are generally mismatched with respect to lattice constant, thermal expansion coefficient, and chemical bonding to the most appropriate commercially available substrates (Si, Ge, and GaAs). For the specific case of III-V semiconductor heteroepitaxy, one must contend with the strain induced by both lattice constant mismatch at the growth temperature and differences in the rates of mechanical deformation during the cool down cycle. Several experimental techniques have been developed to minimize the impact of these phenomena (i.e., compositional grading, strained layer superlattices, and high-temperature annealing). However, in highly strained systems such as InAs-on-GaAs, three-dimensional island formation and large defect densities (greater than or equal to 10(exp 8)/ cm(exp {minus}2)) tend to limit their applicability. In these particular cases, the surface morphology and defect density must be controlled during the initial stages of nucleation and growth. At the last SPRAT conference, the authors reported on a study of the evolution of InAs islands on (100) and (111)B GaAs substrates. Growth on the (111)B orientation exhibits a number of advantageous properties as compared to the (100) during these early stages of strained-layer epitaxy. In accordance with a developing model of nucleation and growth, the authors have deposited thin (60 A - 2500 A), fully relaxed InAs films on (111)B GaAs substrates. Although thicker InAs films are subject to the formation of twin defects common to epitaxy on the (111)B orientation, appropriate control of the growth parameters can greatly minimize their density.
- Research Organization:
- NASA Lewis Research Center, Cleveland, OH (United States)
- OSTI ID:
- 177659
- Report Number(s):
- N-96-15042; NASA-CP-10180; NAS-1.55:10180; E-9943; NIPS-95-05337; CONF-9510288-; CNN: NGT-50832; NSF ECS-92-53760; TRN: 9615058
- Resource Relation:
- Conference: 14. space photovoltaic research and technology conference, Cleveland, OH (United States), 24-26 Oct 1995; Other Information: PBD: Oct 1995; Related Information: Is Part Of Proceedings of the 14th Space Photovoltaic Research and Technology Conference (SPRAT 14); Landis, G.; PB: 47 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Pseudomorphic growth of InAs on misoriented GaAs for extending quantum cascade laser wavelength
Characterization of Heteroepitaxial GaAs Films Grown on Si Using Selective Area Nucleation