Short infrared wavelength quantum cascade detectors based on m-plane ZnO/ZnMgO quantum wells

Research paper by A. Jollivet, B. Hinkov, S. Pirotta, H. Hoang, S. Derelle, J. Jaeck, M. Tchernycheva, R. Colombelli, A. Bousseksou, M. Hugues, N. Le Biavan, J. Tamayo-Arriola, M. Montes Bajo, L. Rigutti, A. Hierro, et al.

Indexed on: 24 Dec '18Published on: 19 Dec '18Published in: Applied physics letters


Applied Physics Letters, Volume 113, Issue 25, December 2018. This paper reports on the demonstration of quantum cascade detectors (QCDs) based on ZnO/ZnMgO quantum wells (QWs) grown by molecular beam epitaxy on an m-plane ZnO substrate. The TM-polarized intersubband absorption is peaked at a 3 μm wavelength. The sample has been processed in the form of square mesas with sizes ranging from 10 × 10 μm2 up to 100 × 100 μm2. The I-V characteristics reveal that 86% of the 260 devices are operational and that the surface leakage current is negligible at room temperature, which is not the case at 77 K. The photocurrent spectroscopy of 100 × 100 μm2 QCDs reveals a photocurrent resonance at a 2.8 μm wavelength, i.e., slightly blue-shifted with respect to the intersubband absorption peak. The photocurrent persists up to room temperature. The calibrated peak responsivity amounts to 0.15 mA/W under irradiation at Brewster's angle of incidence. This value allows us to estimate the transfer efficiency (1.15%) of the photoexcited electrons into the active QW of the next period.