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Bedair, S. M.

Publications and source records attributed to Bedair, S. M..

6 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

p-n junction formation in InSb and InAs(1-x)Sb(x) by metalorganic chemical vapor deposition

p-n junctions have been fabricated in InSb and InAs(1-x)Sb(x)(0.4 less than x less than 0.7) using metalorganic chemical vapor deposition. These junctions showed soft breakdown in addition to forward characteristics with a diode factor greater than 2. The ternary alloy has a cut-off wavelength in the 8-11-micron range, thus providing a potential material system for detectors covering the 8-12-micron range.

Chiang, P. K.↗
NASA NTRS1984

Growth of InSb and InAs(1-x)Sb(x) by OM-CVD

Organometallic chemical vapor deposition (OM-CVD) growth of InSb and InAs(1-x)Sb(x) has been obtained using triethylindium (TEI), trimethylantimony (TMS), and arsine (AsH3) on (100) GaAs, (100) InSb, and (111)-B InSb substrates. InSb with excellent morphology was achieved on both (100) InSb and (111)-B InSb substrates. The measured electron mobility at 300 K of undoped InSb grown on (100) GaAs semi-insulating substrates was 40,000 sq cm/V-s at a carrier concentration of ND-NA = 2.0 x 10 to the 16th per cu cm. Carrier concentration of ND-NA = 1.2 x 10 to the 15th per cu cm has been measured at 77 K. InAs(1-x)Sb(x) (x = 0.07-0.75) with mirror-like surfaces have been grown on (100) InSb and InAs substrates. This composition range of x between 0.55 and 0.75 (Eg = 0.1 eV) has been successfully achieved for the first time. Solid composition variations as a function of growth temperature and InSb substrate orientations are also discussed.

Chiang, P. K.↗
NASA NTRS1980

Fabrication of AlGaAs/GaAs cascade solar cell by LPE

Stacking two or more photovoltaic junctions in electrical and optical series results in higher conversion efficiency since each junction can be tailored to respond more efficiently to a smaller range of photon energies. An efficiency of about 30 percent was predicted for a two junction cascade cell having the optimum bandgap values. A number of III-V materials systems were considered for use in fabricating cascade solar cells. The Al-Ga-As system is attractive from a developmental standpoint since it employs a proven materials system that is closely lattice matched throughout its compositional range. This system employs a GaAs low bandgap cell and 1.9 eV AlGaAs high bandgap cell connected by an AlGaAs tunnel junction. Although this cell does not possess the optimum bandgap values, an efficiency of 25 percent was predicted at 300 K under AMO, 1 sun illumination.

Bedair, S. M.↗