Resonant cavity-enhanced quantum-dot infrared photodetectors with sub-wavelength grating mirror

Abstract

We propose and simulate a device structure of resonant cavity-enhanced quantum-dot infrared photodetector (RCE-QDIP). The RCE-QDIP consists of a conventional n-in QDIP sandwiched by a bottom GaAs/Al 2 O 3 distributed Bragg reflector and a top mirror of Ge/SiO 2 sub-wavelength grating. Aiming for detecting mid-infrared at 8 lm, the total thickness of the device is only $7.7 lm. According to our simulation, the external quantum efficiencies of RCE-QDIP could be as high as 59%-78% with the enhancement factors of 7-30, compared with a conventional QDIP. The proposed RCE-QDIP is highly feasible as the various fabrication parameters are considered.

Guided-mode resonance gratings for enhanced mid-infrared absorption in quantum dot intermediate-band solar cells

“…In [12] three-fold absorbance enhancement was predicted over a 120 nm bandwidth next to the silicon gap and ±40 o angle of incidence, while a 30% integrated absorbance enhancement in the 450 nm -750 nm range was experimentally demonstrated for amorphous silicon cells in [13]. Finally, the resonant-cavity enhanced QDIP in [14] showed absorbance enhancement of 20 at the target wavelength of 8 µm for ±10 o angle of incidence. The IB energy and optical properties depend on several QD parameters such as size and materials.…”

“…Enhancing QD optical transitions in the MIR range is also a key task in the development of QD infrared detectors (QDIP). The use of a GMR grating on the top surface and a distributed Bragg reflector on the bottom has been proposed in [14] to implement resonant-cavity enhanced QDIPs. Taking advantage of the thin-film architecture in [9], we propose here a design wherein the GMR grating is patterned at the rear surface of the cell, leaving room for the optimization of the cell antireflection characteristics through multilayer and/or nanostuctured gratings [15,16] realized on the top surface of the cell.…”

Long-wavelength mid-infrared reflectors using guided-mode resonance

“…The much thinner thickness and flexibility during device processing enables us to fabricate a high-reflectivity mirror in a desired band in the long-wavelength mid-IR regime. Such a reflector can be used, for example, to fabricate a resonant cavity to enhance the quantum efficiency of the quantum-dot IR photodetectors with responsivity spectra ranging from 7.5 to 8.5 μm [14,15]. These GMR reflectors can find their applications aiming for different wavelengths in mid-IR regime due to their flexibility.…”

Emerging technologies for high performance infrared detectors

“…Another disadvantage is an increase of the allowed operating temperature because of the shift of the BLIP limit [184]. RCE structures were used to improve performance in almost all IRPD systems such as p-i-n diodes [185], QW [181], T2SL [186], QD [187], quantum dot in quantum well [188], and light emitting diodes [189].…”