Dark Current Analysis in InAs Quantum-dot APDs with Different Mesa Structures
Dark Current Analysis in InAs Quantum-dot APDs with Different Mesa Structures
- 주제(키워드) InAs quantum-dots (QDs) , Avalanche photodiode (APD) , Dark current , Mesas
- 발행기관 한국물리학회
- 발행년도 2009
- 총서유형 Journal
- UCI G704-000411.2009.55.3.068
- KCI ID ART001497682
- 본문언어 영어
초록/요약
We investigated the changes in the dark currents in InAs quantum-dot (QD) avalanche photodiodes (APDs) with different shapes of mesas. The APDs were fabricated by using inductively coupled plasma/reactive ion etching (ICP/RIE) or H3PO4 chemical etching. The dark currents (Idark) were observed to be 27 pA for the H3PO4-treated APD and 10 pA for the ICP/RIE-treated APD at −11 V at room temperature (RT). Then, to identify the effect of the mesas on the Idark of APDs, we measured the temperature-dependent (TD) I-V and C-V characteristics. As a result, we found that at temperatures below 200 K, the TD Idark of the H3PO4-treated APD was still 3 times larger than that of the ICP/RIE- treated APD, while the change of capacitance ( C) was 1.09 nF for the H3PO4-treated APD and 0.63 nF for the ICP/RIE-treated APD at voltages from 0 V to −12 V. These results indicate that the Idark of the APDs may be strongly affected by mesas and by the surface conditions of the device and that bulk tunneling and surface leakage shunt currents due to strong electric fields may be the dominant components that determine the Idark of the H3PO4-treated APD.
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