Abstract
We simulated and analyzed a resonant-cavity-enhancedd InGaAs/GaAs quantum dot n-i-n photodiode using Crosslight Apsys package. The resonant cavity has a distributed Bragg reflector (DBR) at one side. Comparing with the conventional photodetectors, the resonant-cavity-enhanced photodiode (RCE-PD) showed higher detection efficiency, faster response speed, and better wavelength selectivity and spatial orientation selectivity. Our simulation results also showed that when an AlAs layer is inserted into the device structure as a blocking layer, ultralow dark current can be achieved, with dark current densities 0.0034 A/cm at 0 V and 0.026 A/cm at a reverse bias of 2 V. We discussed the mechanism producing the photocurrent at various reverse bias. A high quantum efficiency of 87.9% was achieved at resonant wavelength of 1030 nm with a FWHM of about 3 nm. We also simulated InAs QD RCE-PD to compare with InGaAs QD. At last, the photocapacitance characteristic of the model has been discussed under different frequencies.
Highlights
Low dimensional III–V semiconductor nanostructures have been widely studied on their electronic and optical properties for device applications
A resonant-cavity-enhanced photodiode (RCE-PD) is usually constructed by placing multiple active layers at the peak positions of a standing wave in a resonant cavity, sandwiched between two distributed Bragg reflectors (DBRs)
The DBR mirrors are usually made of quarter wave stacks with a periodic modulation of refractive indices
Summary
Low dimensional III–V semiconductor nanostructures have been widely studied on their electronic and optical properties for device applications. Compared with the conventional detectors, the responsivity is greatly improved This makes the RCE-PD with high detection efficiency, fast response speed, ability to work in the absence of bias voltage, and their wavelength selectivity and spatial orientation selectivity especially suitable for optical fiber communication system that requires high wavelength accuracy. To achieve high sensitive detection at this wavelength, resonant-cavity-enhanced- (RCE-) PDs with quantum dots (QDs) as absorption layers were explored to reach a peak quantum efficiency of 65–75% [8,9,10]. DBR mirrors make it difficult for the device to extract photogenerated carriers To solve this problem, Bennett et al and Sun et al fabricated an InGaAs/GaAs quantum dot n-i-n RCE-PDs with only a bottom DBR mirror which still has the resonant coupling nature and achieved peak photoresponsivity of 0.75 A/W at 1.4 V [11, 12]
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