A route to high gain photodetectors through suppressed recombination in disordered films
Journal Publication ResearchOnline@JCUAbstract
Secondary photocurrents offer an alternative mechanism to photomultiplier tubes and avalanche diodes for making high gain photodetectors that are able to operate even at extremely low light conditions. While in the past secondary currents were studied mainly in ordered crystalline semiconductors, disordered systems offer some key advantages such as a potentially lower leakage current and typically longer photocarrier lifetimes due to trapping. In this work, we use numerical simulations to identify the critical device and material parameters required to achieve high photocurrent and gain in steady state. We find that imbalanced mobilities and suppressed, non-Langevin-type charge carrier recombination will produce the highest gain. A low light intensity, strong electric field, and a large single carrier space charge limited current are also beneficial for reaching high gains. These results would be useful for practical photodetector fabrication when aiming to maximize the gain.
Journal
Applied Physics Letters
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Volume
109
ISBN/ISSN
1077-3118
Edition
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Issue
15
Pages Count
4
Location
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Publisher
American Institute of Physics
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Publisher Location
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Date
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EISSN
N/A
DOI
10.1063/1.4963705