Analysis of uniformity of as prepared and irradiated S.I. GaAs radiation detectors

Journal Article · Mon Jun 01 04:00:00 EDT 1998 · IEEE Transactions on Nuclear Science

DOI:https://doi.org/10.1109/23.682458· OSTI ID:624192

Nava, F; Vanni, P; Canali, C ^[1]; Apostolo, G; Manfredotti, C; Polesello, P; Vittone, E ^[2]

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1. Univ. di Modena (Italy)
2. Univ. di Torino (Italy). Dipt. di Fisica Sperimentale

SI (semi-insulating) LEC (Liquid Encapsulated Czochralsky) GaAs (gallium arsenide) Schottky barrier detectors have been irradiated with high energy protons (24 GeV/c, fluence up to 16.45 {times} 10{sup 13} p/cm{sup 2}). The detectors have been characterized in terms of I/V curves, charge collection efficiency (cce) for incident 5.48 MeV {alpha}-, 2 MeV proton and minimum ionizing {beta}-particles and of cce maps by microprobe technique IBIC (Ion Beam Induced Charge). At the highest fluence a significant degradation of the electron and hole collection efficiencies and a remarkable improvement of the Full Width Half Maximum (FWHM) energy resolution have been measured with {alpha}- and proton particles. Furthermore, the reduction in the cce is greater than the one measured with {beta}-particles and the energy resolution worsens with increasing the applied bias, V{sub a}, above the voltage V{sub d} necessary to extend the electric field al the way to the ohmic contact. On the contrary, in the unirradiated detectors the charge collection efficiencies with {alpha}-, {beta}- and proton particles are quite similar and the energy resolution improves with increasing V{sub a} > V{sub d}. IBIC spectra and IBIC space maps obtained by scanning a focused (8 {micro}m{sup 2}) 2 MeV proton microbeam on front (Schottky) and back (ohmic) contacts, support the observed electric field dependence of the energy resolution both in unirradiated and most irradiated detectors. The results obtained let them explain the effect of the electric field strength and the plasma on the collection of the charge carriers and the FWHM energy resolution.

• OSTI ID: 624192
• Report Number(s): CONF-971147--
• Journal Information: IEEE Transactions on Nuclear Science, Journal Name: IEEE Transactions on Nuclear Science Journal Issue: 3Pt1 Vol. 45; ISSN 0018-9499; ISSN IETNAE
• Country of Publication: United States
• Language: English

Related Subjects

44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
ALPHA PARTICLES
CHARGE COLLECTION
ENERGY RESOLUTION
GALLIUM ARSENIDES
PHYSICAL RADIATION EFFECTS
SCHOTTKY BARRIER DIODES
SEMICONDUCTOR DETECTORS
SOLID-STATE PLASMA