Design and measurements of the absorption section of an up-conversion device based on PbSe quantum-dots

Abstract

The absorption section of quantum dots (QD) based night vision devices consists of the OQ sensitizing layer which absorbs the Infrared radiation, the substrate on which the QD are placed, the electrode and, in several cases, a blocking layer that prevents the flow of charge carriers toward the inverse direction. The absorption section plays a dominant role in determining the absorption spectral ranges and the signal-to-noise ratios of the devices. In this work, we show the design of the absorption section of a short wavelength infrared (SWIR) to visible direct up-conversion device. The growth was 300nm thick PbSe quantum dots (QD) separated by PbSe grain boundaries layer on intrinsic GaAs substrate. Photo-luminescence and absorption measurements suggested that the quantum dots spectral response is blue-shifted to the spectral range in which the up-conversion device is operated i.e., SWIR. We preformed sheet resistance measurements in dark and under illumination that showed that the device exhibits an improvement in the signal-to-noise ratio after annealing ion chloride atmosphere compare with annealing in oxygen atmosphere. These samples have great potential for the use as the absorption section of low-cost, compact, low power consumption, and cooler free up-conversion devices.