Optimization of a HOT LWIR HgCdTe Photodiode for Fast Response and High Detectivity in Zero-Bias Operation Mode

摘要: Fast response is an important property of infrared detectors for many applications. Currently, high-temperature long-wavelength HgCdTe heterostructure photodiodes exhibit subnanosecond time constants while operating under reverse bias. However, nonequilibrium devices excessive low-frequency 1/f noise that extends up to MHz range, representing a severe obstacle their widespread application. Present efforts are focused on zero-bias operation photodiodes. Unfortunately, the constant unbiased still at level several nanoseconds. We present herein theoretical investigation device design improved and detectivity 230 K in mode. The calculation results show highly doped p-type absorber material choice fast due its high electron diffusion coefficient. such can also be optimized by using doping N A = 1 × 1017 cm−3. Reduction thickness yet another approach improve response. Time below ns achieved photodiode with 4 μm. tradeoff between contradictory requirements achieving expected optically immersed very small active area.