Speaker
Description
Staircase avalanche photodetectors have been shown to exhibit reduced noise, controlled gain, and enhanced signal amplification compared to standard avalanche photodetectors. Devices fabricated from superlattices of amorphous selenium and arsenic selenide have demonstrated linear multiplicative behavior through quantum tunneling based on the number of layers employed, allowing for specific gains to be realized. However, further work is needed to reduce carrier trapping, improve multiplication in thick layers, and better understand detector noise. To determine our system's capability to deposit these thin amorphous superlattices, we have fabricated amorphous Se/Se–Te multilayer photodetectors with varying Te concentrations and investigated the properties of these quantum layers. Se-Te alloys have been extensively studied to show that varying the Te concentration provides precise control over the band gap of the material. The fabricated thin films were characterized using ellipsometry, photothermal deflection spectroscopy (PDS), UV–Vis spectroscopy, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) to evaluate their optical, morphological, and compositional properties. Continuing work will investigate superlattice device behavior, signal amplification, and noise reduction.
This work was supported by U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0026034 and DE-SC0022343 and the UCSC REU program through the National Science Foundation (Grant # 2349305).