Methods for characterization of trapping centers in semiconductors with application to niobium dioxide, gallium arsenide, cadmium telluride and indium phosphide

Thesis/Dissertation · Sat Jan 01 00:00:00 EST 1983

OSTI ID:6612761

Yousuf, M M

Several of the techniques for trapping centers characterization are briefly presented. Three of these techniques: admittance spectroscopy (AS), thermally stimulated current (TSC) and space charge limited current (SCLC) are discussed in more detail and were applied to NbO/sub 2/ single crystal and polycrystalline, GaAs, CdTe and InP materials. Application of AS to single crystal NbO/sub 2/ revealed the existence of 5 trapping centers with energy levels varying between 0.25 to 0.435 eV. Trapping levels in polycrystalline NbO/sub 2/ are found to be contact dependent. Thermoelectric power measurements on polycrystalline NbO/sub 2/ before and after switching indicate the possibility that switching occurs throughout the entire device volume and not by the filament formation as previously assumed. A layer of Ge/sub 3/N/sub 4/ was deposited as a dielectric on GaAs epitaxial layer in order to passivate its surface. MIS devices were thus fabricated with a low surface state density (4.6 x 10/sup 4/ cm/sup -2/ eV/sup -1/) using this technique. CdTe samples before and after neutron irradiation were studied using AS, TSC and SCLC techniques. Four trapping levels at 0.17 to 0.53 eV were detected in non-irradiated samples, while an additional trap level at an energy level of 0.7 eV with a trap density of 7 x 10/sup 11/cm/sup -3/ was found in the irradiated samples. Pd-InP Schottky diodes are found to be sensitive gaseous sensors for hydrogen and hydrocarbons. Change in either device capacitance or current at constant voltage was used to measure the adsorption and desorption time constants of the device transient behavior.

• OSTI ID: 6612761
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CADMIUM TELLURIDES
PHYSICAL RADIATION EFFECTS
TRAPPING
GALLIUM ARSENIDES
INDIUM PHOSPHIDES
NIOBIUM OXIDES
NEUTRONS
SPECTROSCOPY
ARSENIC COMPOUNDS
ARSENIDES
BARYONS
CADMIUM COMPOUNDS
CHALCOGENIDES
ELEMENTARY PARTICLES
FERMIONS
GALLIUM COMPOUNDS
HADRONS
INDIUM COMPOUNDS
NIOBIUM COMPOUNDS
NUCLEONS
OXIDES
OXYGEN COMPOUNDS
PHOSPHIDES
PHOSPHORUS COMPOUNDS
PNICTIDES
RADIATION EFFECTS
TELLURIDES
TELLURIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360605* - Materials- Radiation Effects