Defect-related surface currents in InAs-based nBn infrared detectors
| Autor: | Brendan T. Marozas, G. R. Savich, Gary W. Wicks, X. Du |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Surface diffusion Materials science Condensed matter physics business.industry Band gap Dangling bond General Physics and Astronomy 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Barrier layer Semiconductor 0103 physical sciences Diffusion current 0210 nano-technology business Quantum tunnelling Dark current |
| Zdroj: | Journal of Applied Physics. 123:214504 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.5027637 |
| Popis: | Surface currents in mid-wave infrared photodetectors often limit the device performance. Dark current mechanisms in the bulk of a semiconductor are well understood; however, there is a poorer understanding of the mechanisms of surface currents. This work shows the existence of two types of surface current: Shockley-Read-Hall generated diffusion current and trap-assisted tunneling (TAT) through the unipolar barrier of nBn. The surface diffusion current exhibits a thermal activation energy equal to the full bandgap of InAs. Both of these surface current mechanisms are related to defects on the sidewall of the device mesa. Due to etch damage and dangling bonds, the surface defect density is typically large; thus, defect-related surface currents can be much larger than their bulk counterparts. The characteristics and temperature dependence of the surface diffusion current in two nBn structures, deep-etched (etched through the barrier layer) nBn and inverted nBn, have been shown to agree with the theory. Evidence of surface TAT current is shown in deep-etched nBn.Surface currents in mid-wave infrared photodetectors often limit the device performance. Dark current mechanisms in the bulk of a semiconductor are well understood; however, there is a poorer understanding of the mechanisms of surface currents. This work shows the existence of two types of surface current: Shockley-Read-Hall generated diffusion current and trap-assisted tunneling (TAT) through the unipolar barrier of nBn. The surface diffusion current exhibits a thermal activation energy equal to the full bandgap of InAs. Both of these surface current mechanisms are related to defects on the sidewall of the device mesa. Due to etch damage and dangling bonds, the surface defect density is typically large; thus, defect-related surface currents can be much larger than their bulk counterparts. The characteristics and temperature dependence of the surface diffusion current in two nBn structures, deep-etched (etched through the barrier layer) nBn and inverted nBn, have been shown to agree with the theory. Evide... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|