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Proceedings Paper

Vapor phase epitaxy growth of CdTe epilayers for RT x-ray detectors
Author(s): Nico Lovergine; A. M. Mancini; P. Prete; Adriano Cola; Leander Tapfer
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Paper Abstract

We report on the growth of thick CdTe layers on ZnTe/(100) GaAs hybrid substrates by the novel H2 transport vapor phase epitaxy (H2T-VPE) method. High crystalline quality (100)-oriented CdTe single crystal epilayers can be fabricated under atmospheric pressure and at growth temperatures (TD) in the 600 - 800 degree Celsius interval. Double crystal X-ray diffraction measurements performed on epilayers thicker than 30 micrometer show CdTe (400) peaks with FWHM < 59 arcsec. Samples grown under optimized conditions exhibit mirror-like surfaces. Nominally undoped epilayers grown < 650 degrees Celsius are p-type and low resistive, but they turn n-type above 650 degrees Celsius, as a result of donor (likely Ga) diffusion from the substrate. RT resistivities ((rho) ) approximately 106 (Omega) (DOT)cm are obtained for 675 degrees Celsius < TD < 700 degrees Celsius, but (rho) decreases for higher temperatures and thinner samples. Layers grown under these conditions show RT electron concentrations in the 1014 - 1011 cm-3 range. The detection capability of H2T-VPE grown CdTe is demonstrated by time- of-flight measurements performed at RT on Au/n-CdTe/n+- GaAs diode structures under reverse bias conditions. The present results show the potentials of H2T-VPE for the growth of detector-grade CdTe.

Paper Details

Date Published: 21 November 2000
PDF: 10 pages
Proc. SPIE 4141, Hard X-Ray, Gamma-Ray, and Neutron Detector Physics II, (21 November 2000); doi: 10.1117/12.407582
Show Author Affiliations
Nico Lovergine, INFM and Univ. degli Studi di Lecce (Italy)
A. M. Mancini, INFM and Univ. degli Studi di Lecce (Italy)
P. Prete, Istituto per lo studio di nuovi Materiali per l'Elettronica (Italy)
Adriano Cola, Istituto per lo studio di nuovi Materiali per l'Elettronica (Italy)
Leander Tapfer, Ctr. Nazionale per al Ricerca e lo Sviluppo de Materiali (Italy)


Published in SPIE Proceedings Vol. 4141:
Hard X-Ray, Gamma-Ray, and Neutron Detector Physics II
Ralph B. James; Richard C. Schirato, Editor(s)

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