A solid-state amorphous selenium avalanche technology for low photon flux imaging applications.
OBJECTIVE
The feasibility of a practical solid-state technology for low photon flux imaging applications was investigated. The technology is based on an amorphous selenium photoreceptor with a voltage-controlled avalanche multiplication gain. If this photoreceptor can provide sufficient internal gain, it will be useful for an extensive range of diagnostic imaging systems.


METHODS
The avalanche photoreceptor under investigation is referred to as HARP-DRL. This is a novel concept in which a high-gain avalanche rushing photoconductor (HARP) is integrated with a distributed resistance layer (DRL) and sandwiched between two electrodes. The avalanche gain and leakage current characteristics of this photoreceptor were measured.


RESULTS
HARP-DRL has been found to sustain very high electric field strengths without electrical breakdown. It has shown avalanche multiplication gains as high as 10(4) and a very low leakage current (< or = 20 pA/mm2).


CONCLUSIONS
This is the first experimental demonstration of a solid-state amorphous photoreceptor which provides sufficient internal avalanche gain for photon counting and photon starved imaging applications.
Department of Medical Biophysics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario M4N 3M5, Canada. matt.wronski@utoronto.ca
M M
MM
Wronski
W
W
Zhao
A
A
Reznik
K
K
Tanioka
G
G
DeCrescenzo
J A
JA
Rowlands
D003952:Diagnostic Imaging / Q000379:methods*; D004553:Electric Conductivity; D004566:Electrodes; D017785:Photons; D012643:Selenium / Q000737:chemistry*
D012643:Selenium