Accession Number : ADA284310


Title :   Silicon Carbide Photoconductive Switches


Descriptive Note : Final rept. Oct 1992-Dec 1993


Corporate Author : ARMY RESEARCH LAB ADELPHI MD


Personal Author(s) : Saddow, Stephen E.


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA284310


Report Date : SEP 1994


Pagination or Media Count : 27


Abstract : The optoelectronic properties of p-type 6-H silicon carbide (6H-SiC) have been investigated in an experiment that used lateral and vertical photoconductive (PC) switches. Both photovoltaic and photoconductive effects are reported, which were observed on switches using both geometries and measured at several wavelengths near the 6H-SiC absorption edge. PC techniques were employed to measure the surface and bulk carrier lifetimes of 40 and 200 ns, respectively. The switches displayed a high-speed photovoltaic response to picosecond laser excitations in the UV and visible spectral regions. In particular, efficient subnanosecond optical absorption processes were observed in the visible region. The photovoltage was measured as a function of both laser wavelength (and hence absorption depth) and laser beam position within the switching gap. The switch response to picosecond laser pulses in the UV, violet, green, and red spectral regions was shown to have subnanosecond photovoltaic response times. Finally, since the optical absorption coefficient had not been well established for device-grade 6H-SiC, the optical absorption coefficient near the 6H-SiC bandgap energy (Eg) was also measured, and the bandgap was determined to be approximately 3.1 eV. 6H-SiC, Photoconductive, Photovoltaic, Absorption coefficient, Switch, Silicon carbide


Descriptors :   *SILICON CARBIDES , *SWITCHES , *PHOTOCONDUCTIVITY , VELOCITY , FUNCTIONS , OPTICS , EDGES , EXCITATION , RED(COLOR) , ENERGY , VOLTAGE , SEMICONDUCTORS , LASER BEAMS , DEPTH , REGIONS , SURFACES , PULSES , RESPONSE , GEOMETRY , VISIBLE SPECTRA , ULTRAVIOLET SPECTRA , ABSORPTION COEFFICIENTS , GREEN(COLOR) , SWITCHING , PHOTOVOLTAIC EFFECT


Subject Categories : INORGANIC CHEMISTRY
      ELECTRICAL AND ELECTRONIC EQUIPMENT
      ELECTROOPTICAL AND OPTOELECTRONIC DEVICES
      ELECTRICITY AND MAGNETISM


Distribution Statement : APPROVED FOR PUBLIC RELEASE