Presentation Details
| LCL Design Constraints in 3T PV/LPC Tandems for Lunar Applications Elijah Sacchitella1, Katelynn Fleming1, Glenn Hillier2, Noren Pan2, Seth Hubbard1, Anastasia Soeriyadi2. 1Nano Power Research Lab, Rochester, NY, USA.2MicroLink Devices Inc, Niles, IL, USA |
Abstract
3T photovoltaic/laser power converter (PV/LPC) tandems offer a promising approach for sustained lunar power systems but introduce coupled electrical, optical, and radiation constraints through the lateral conduction layer (LCL). In this work, LCL design is evaluated using fractional power loss (FPL) modeling, optical absorption analysis, and SRIM simulations across lattice matched materials to InP. FPL modeling shows that high injection LPC operation dictates micron scale LCL thicknesses to limit resistive losses, with strong dependence on carrier mobility. Under 4 W/cm² operation, thickness requirements increase significantly compared to photovoltaic conditions, particularly for lower mobility materials. However, these thicknesses introduce competing constraints. For example, an In₀.₅₃Ga₀.₄₇As LCL thickness of ~1.7 μm, required to maintain FPL below 5%, results in approximately 25% absorption of incident 1064 nm light, directly reducing the optical power available for LPC conversion. These thicknesses are also comparable to proton penetration depths, linking electrical design to radiation response. SRIM simulations for 1 MeV protons show that increasing LCL thickness shifts radiation-induced damage deeper into the device and increases defect generation within the LCL, while also promoting damage in the bottom cell. This indicates that LCL thickness can be used to influence damage distribution, but does not fully confine damage to the LCL region. Among the materials considered, InP provides a balanced design space by avoiding parasitic absorption while enabling thicknesses suitable for damage localization.
Initial InP PV devices demonstrate promising voltage (Voc = 0.888 V) but reduced carrier collection, with EQE indicating front-side transport limitations consistent with the InAlAs/InP interface. These results highlight the coupled nature of LCL and interface design and establish the LCL as a key parameter governing electrical performance, optical loss, and radiation response in 3T PV/LPC systems.
No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.
Initial InP PV devices demonstrate promising voltage (Voc = 0.888 V) but reduced carrier collection, with EQE indicating front-side transport limitations consistent with the InAlAs/InP interface. These results highlight the coupled nature of LCL and interface design and establish the LCL as a key parameter governing electrical performance, optical loss, and radiation response in 3T PV/LPC systems.
No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.
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