Minority carrier diffusion lengths and mobilities in low-doped n-InGaAs for focal plane array applications

The hole diffusion length in n-InGaAs is extracted for two samples of different doping concentrations using a set of long and thin diffused junction diodes separated by various distances on the order of the diffusion length. The methodology is described, including the ensuing analysis which yields diffusion lengths between 70 - 85 um at room temperature for doping concentrations in the range of 5 - 9 x 10^15 cm-3. The analysis also provides insight into the minority carrier mobility which is a parameter not commonly reported in the literature. Hole mobilities on the order of 500 - 750 cm2/Vs are reported for the aforementioned doping range, which are comparable albeit longer than the majority hole mobility for the same doping magnitude in p-InGaAs. A radiative recombination coefficient of (0.5-0.2)x10^-10 cm^-3s^-1 is also extracted from the ensuing analysis for an InGaAs thickness of 2.7 um. Preliminary evidence is also given for both heavy and light hole diffusion. The dark current of InP/InGaAs p-i-n photodetectors with 25 and 15 um pitches are then calibrated to device simulations and correlated to the extracted diffusion lengths and doping concentrations. An effective Shockley-Read-Hall lifetime of between 90-200 us provides the best fit to the dark current of these structures.Comment: 9 pages, 5 figure

Heavy and light hole minority carrier transport properties in low-doped n-InGaAs lattice matched to InP

Minority carrier diffusion lengths in low-doped n-InGaAs using InP/InGaAs double-heterostructures are reported using a simple electrical technique. The contributions from heavy and light holes are also extracted using this methodology, including minority carrier mobilities and lifetimes. Heavy holes are shown to initially dominate the transport due to their higher valence band density of states, but at large diffusion distances, the light holes begin to dominate due to their larger diffusion length. It is found that heavy holes have a diffusion length of 54.5 +/- 0.6 microns for an n-InGaAs doping of 8.4 x 10^15 cm-3 at room temperature, whereas light holes have a diffusion length in excess of 140 microns. Heavy holes demonstrate a mobility of 692 +/- 63 cm2/Vs and a lifetime of 1.7 +/- 0.2 microsec, whereas light holes demonstrate a mobility of 6200 +/- 960 cm-2/Vs and a slightly longer lifetime of 2.6 +/- 1.0 microsec. The presented method, which is limited to low injection conditions, is capable of accurately resolving minority carrier transport properties.Comment: 16 pages, 13 figure

Metropolitan-Micropolitan Difference in Available Labor Force Characteristics: Three Great Plains Labor Basins

This study explores differences in labor availability characteristics among those living in metropolitan and micropolitan areas. Data used in this study are from surveys of adults in two adjacent Midwestern states and from three separate labor basins. Primary patterns under examination include wage demands, benefit demands, distance willing to commute for a job, perceived underemployment and entrepreneurial propensity. Bivariate analyses show no relationship between basin size and entrepreneurial propensity nor between basin size and willingness to commute. However, basin size has significant influence on four of the seven dependent variables, even after controlling for many sociodemographic characteristics. In multivariate analyses, health benefits, retirement benefits, education assistance and underemployed for skills continue to be significantly associated with size of basin, while desired wage, on the job (OJT) or paid training and underemployed for education are not significantly associated. Micropolitan area available labor pool (ALP) members place more importance on health benefits, retirement benefits and education assistance in considering new employment than do metropolitan ALP members. Among employed ALP, metropolitan respondents have a stronger perception of being underemployed given their skill level. These data are from only three labor basin areas. Variation is highly restricted due to the small number of places for comparative analysis. Future research will incorporate additional labor basins

Neglect Benevolence in Human-Swarm Interaction with Communication Latency

In practical applications of robot swarms with bio-inspired behaviors, a human operator will need to exert control over the swarm to fulfill the mission objectives. In many operational settings, human operators are remotely located and the communication environment is harsh. Hence, there exists some latency in information (or control command) transfer between the human and the swarm. In this paper, we conduct experiments of human-swarm interaction to investigate the effects of communication latency on the performance of a human-swarm system in a swarm foraging task. We develop and investigate the concept of neglect benevolence, where a human operator allows the swarm to evolve on its own and stabilize before giving new commands. Our experimental results indicate that operators exploited neglect benevolence in different ways to develop successful strategies in the foraging task. Furthermore, we show experimentally that the use of a predictive display can help mitigate the adverse effects of communication latency

Tax planning tips 1981 from the Tax adviser

https://egrove.olemiss.edu/aicpa_guides/2774/thumbnail.jp

Tax planning tips 1980 from the Tax adviser

https://egrove.olemiss.edu/aicpa_guides/2773/thumbnail.jp

Tax planning tips 1982 from the Tax adviser

https://egrove.olemiss.edu/aicpa_guides/2775/thumbnail.jp