Degradation Study of MOVPE‐Grown and Zinc‐Diffused GaSb Cells for Thermophotovoltaic Applications

GaSb‐based cells are promising candidates for use in thermophotovoltaic (TPV) systems. In order to assess long term cell performance, suitable accelerated ageing tests are required. So far there are no studies concerning the degradation behaviour of GaSb cells. GaSb‐based cells produced from MOVPE‐grown structures and from zinc vapour diffused structures have been examined. Due to the different device structure, these two types differ in their fabrication technology and also in the anti‐reflection coatings (ARC). Two different methods for accelerated ageing have been tested on these cells for TPV applications. The first involves forward bias at an elevated current density equivalent to that which is expected to flow in the real operating TPV system. The second test, storage in a humid (100%) atmosphere at 95°C, examines degradation due to oxidation processes. The behaviour in degradation is found to depend on the specific test condition and on the structure of the cell. In general, the diffused cell struc...