The extended InGaAs short wavelength infrared (SWIR) detector covers 1.0-2.5 μm wavelength, which plays an important role in weather forecast, resource observation, low light level systems, and astronomical observation and so on. In order to fabricate the high performance extended InGaAs detector, materials structure and parameters were characterized with Scanning Capacitance Microscopy (SCM), Scanning Spreading Resistance Microscopy (SSRM), the spreading of minority carriers and lattice quality were obtained. Mesa etching process, etching damage restoration technique and low temperature passivation technique were used in the fabrication of the extended InGaAs detector. The improvement of material structure and device process was studied by fabricating and measuring different perimeter-to-area (P/A) photodiodes and singledevice, respectively. The dark current density of the extended InGaAs detector obviously was reduced, about 2 nA/cm<sup>2</sup> at 170 K. The 512×256 FPAs were fabricated, the peak detectivity and the quantum efficiency of which are 5×10<sup>11</sup> cmHz<sup>1/2</sup>/W and 80%, respectively. The staring image yielded of the 512×256 FPAs is shown, which demonstrates very good imaging quality.
Extended wavelength InGaAs infrared detector arrays in 1.0~2.5μm spectral rang based on three types of material structures grown by MBE were studied. The first type InGaAs detectors, marked by sample 1#, were fabricated using Pi- N epitaxial materials, mesa etching technique, side-wall and surface passivating film. The second type InGaAs detectors, marked by sample 2#, were fabricated using N-i-P epitaxial materials, mesa etching technique, side-wall and surface passivating film. The third type InGaAs detectors, marked by sample 3#, were fabricated using n-i-n epitaxial materials, planar diffusion process and surface passivating coating. I-V curves, low frequency noise and response spectra of these detectors were measured at the different temperature. The response spectra of these detectors cover 1.0~2.5μm wavelength range. The dark current density of three types InGaAs detectors are 28nA/cm<sup>2</sup>, 2μA/cm<sup>2</sup>, 9μA/cm<sup>2</sup> at 200K and -10mV bias voltage, respectively. Compared to Sample 2# and Sample 3#, sample 1# presents the lower dark current at the same temperature and the same bias voltage, which mainly results in the improvement of surface passivation film and the depth of mesa etching. The frequency spectrum of the noise of sample 1# has an inflection point at about 10Hz frequency, 1/f noise play an obviously role in the detectors below the 10Hz frequency.
InP-based antimony-free In<sub>0.53</sub>Ga<sub>0.47</sub>As/InAs/In<sub>0.53</sub>Ga<sub>0.47</sub>As strained triangular quantum well lasers have been demonstrated for the light sources with wavelength beyond 2 μm. Theoretical estimation shows that the triangular quantum well owns the longer emission wavelength than the rectangular quantum well with the same strain extent. The triangular quantum well was formed experimentally by using gas source molecular beam epitaxy grown digital alloy, and the growth temperature of the triangular quantum wells was optimized. The triangular quantum well lasers with emission beyond 2.2 μm under continuous-wave operation at temperatures higher than 330 K have been demonstrated. The performances of the triangular quantum well lasers are improved comparing to those of InAs rectangular quantum lasers with the nearly same lasing wavelength.
The thermal characteristics of 1 .3 µ m ridge waveguide InAsP/InGaAsP MQW lasers, including their temperature distribution and thermal resistance, have been simulated by using finite-element methods. The process of three-dimensional model of laser simulation is presented in this paper. The results show that FEM is a useful tool to simulate the thermal conditions of the lasers, which are critical to the design of the laser structure as well as package.
Conference Committee Involvement (1)
Infrared Optoelectronics: Materials and Devices
4 September 2012 | Evanston, Illinois, United States