Performance Variations in Proton-Bombarded Industry-Grade CdSeTe:Cu and CdSeTe:As PV Devices

As part of an ongoing effort to qualify cadmium selenide telluride- (CdSeTe-) based photovoltaic (PV) devices for use in space applications, industry-grade CdSeTe PV devices have been exposed to high-energy proton irradiation (150-to-1500 keV particles with fluences ranging from 1 x 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> to 9 x 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sup> cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−2</sup>), with their current density vs. voltage (JV) characteristics and external quantum efficiency (EQE) subsequently measured. Raw JV results show arsenic-doped CdSeTe devices retain 80% of the power conversion efficiency (PCE) of unexposed controls when exposed to 650 keV protons at 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−2</sup> fluence. Copper-doped CdSeTe devices fair even better under those same irradiation conditions, retaining about 95% of control device PCE. The main driver of PCE differences at high proton fluence exposure conditions is the precipitous drop in short-circuit current density, which was corroborated with depressed EQE measured at those same irradiation conditions.