Infrared Detectors Using Mercury Manganese Telluride

In the proposed research we will investigate methods for improving the performance of very long wavelength infrared (VLWIR) photovoltaic detectors fabricated from Hg1-xMnxTe. This material was chosen because Hg1-xMnxTe has been shown to have superior mechanical, chemical and thermal stability compared Hg1-xCdxTe. During previously SBIR-BMDO funded work, Brimrose Corporation successfully fabricated Hg1-xMnxTe detectors with cutoff wavelengths of 15.5 microns at 77 K, RoA performance in excess of 0.02Qcm2 and minority carrier lifetimes of 1 microsecond. The bulk Hg1-xMnxTe crystals were grown using the travelling heater method (TJM). Further purification of the starting materials and processing techniques along with a substantial reduction in diode thickness is expected to improve these parameters such that the minority carrier lifetimes approach the Auger limits. Therefore, we propose liquid phase epitaxial growth (LPE) of Hg1-xMnxTe layers on lattice matched Hg1-xMnxTe substrates via the tipping and dipping techniques to fabricate very thin n on p photodetectors. We will also investigate extensive methods for further purification of the starting materials and the solutions necessary for LPE growth. Phase I of this project will investigate the feasibility of such improvements. After these improvements have been successfully demonstrated, optimization of the growth techniques and the development of linear and focal plane arrays will be the focus of phase II. Subsequent to the phase II program, results of this research will be commercialized.