Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “n-Type Doping”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Zn diffusion in Al/0.7/Ga/0.3/As compared with that in GaAs

Zinc was diffused into 4 times 10 to the 17th per cu cm n-type Al(0.7)Ga(0.3)As grown by liquid-phase epitaxy and also into n-type 2 times 10 to the 17th per cu cm doped GaAs slices at 600, 650, and 750 C. The Zn diffusion coefficient in the Al(0.7)Ga(0.3)As was about one order of magnitude larger than in GaAs. The significance of this fact is that diffusion of Zn through a 0.5 micron Al(0.7)Ga(0.3)As layer appears to be possible with adequate control of the junction depth in the underlying GaAs.

Flat, A.↗
NASA NTRS1979

Radiation effects in GaAs AMOS solar cells

The results of radiation damage produced in AMOS (Antireflecting-Metal-Oxide-Semiconductor) cells with Sb2O3 interfacial oxide layers by 1-MeV electrons are presented. The degradation properties of the cells as a function of irradiation fluences were correlated with the changes in their spectral response, C-V, dark forward, and light I-V characteristics. The active n-type GaAs layers were grown by the OM-CVD technique, using sulfur doping in the range between 3 x 10 to the 15th power and 7 x 10 to the 16th power/cu cm. At a fluence of 10 to the 16th power e/sq cm, the low-doped samples showed I sub sc degradation of 8% and V sub oc degradation of 8%. The high-doped samples showed I sub sc and V sub oc degradation of 32% and 1%, respectively, while the fill factor remained relatively unchanged for both. AMOS cells with water vapor-grown interfacial layers showed no significant change in V sub oc.

Shin, B. K.↗
NASA NTRS1977

LPE growth of GaAs-Ga/1-x/Al/x/As solar cells

The procedures for the liquid phase epitaxial (LPE) growth of high efficiency p-Ga(1-x)Al(x)As,p-GaAs,n-GaAs solar cells have been developed. The methods are based on forming the structure by a one-step process in which the Zn-diffused p-n junction in the n-type GaAs substrate forms in conjunction with the LPE growth of the Zn-doped p-Ga(1-x)Al(x)As layer. For structures with 1-10 micron thick Ga(1-x)Al(x)As layers, an isothermal soak of the GaAs substrate in a saturated Ga-Al-As: Zn melt followed by ramp cooling produces good cells. For structures with less than one micron thick Ga(1-x)Al(x)As layers, it is necessary to isothermally soak the GaAs substrate in an undersaturated melt, and ramp cooling is not required.

Woodall, J. M.↗
NASA NTRS1973

Characteristics of infrared photodetectors produced by radiation doping.

High-energy electrons (approximately 7 MeV) were used to radiation-dope extrinsic silicon. Both n- and p-type silicon photodetectors were fabricated using this doping technique. The 500 K blackbody responsivity, spectral response, and peak detectivity were determined for these devices. The peak detectivity values measured were 4.8 Gm Hz to the 1/2 power per W at 2.15 microns for 0.1-ohm-cm n-type devices and 3.7 Gm Hz to the 1/2 power per W at 40 microns for 10-ohm-cm p-type detectors. A comparison of the thermally generated background majority carrier concentration for radiation-doped and conventional impurity-doped detectors is made.

Gross, C.↗
NASA NTRS1977

Surface photovoltage in exciton absorption range in CdS

The high resolution, intrinsic spectra of surface photovoltage are reported for semiconducting n-type CdS single crystals. At reduced temperatures (120-160 K) the spectra exhibit three sharp maxima due to A, B and C free exciton transitions. Energy positions of these lines and valence band parameters (spin-orbit and crystal field splittings) estimated from surface photovoltage are in good agreement with values obtained by other methods. The excitonic transitions are very sensitive to surface treatment, i.e. polishing, etching, background illumination and surface doping. The mechanism of direct interaction of free excitons with surface states is proposed to explain exciton lines in surface photovoltage.

Morawski, A.↗