Ultra-high detectivity room temperature THZ-IR photodetector based on resonant tunneling spherical centered defect quantum dot (RT-SCDQD)

• Published in: Optics communications 2009-09, Vol.282 (17), p.3499-3508
• Main Authors: Saghai, H. Rasooli, Sadoogi, N., Rostami, A., Baghban, H.
• Format: Article
• Language: English
• Subjects: Applied sciences; Bolometer; infrared, submillimeter wave, microwave and radiowave receivers and detectors; Detectivity; Electronics; Exact sciences and technology; Infrared, submillimeter wave, microwave and radiowave instruments, equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Optoelectronic devices; Physics; Quantum dot; Resonant tunneling; Room temperature; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Spherical defect; Terahertz-infrared photodetector
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2009.05.064

In this paper, a novel structure for THZ-IR photodetector based on resonant tunneling spherical centered defect quantum dot (RT-SCDQD) operating at room temperature is proposed. The proposed structure includes a quantum dot with centered defect following a resonant tunneling double barrier. It is shown that inserting a centered defect leads to considerable enhancement in absorption coefficient at long wavelength in small dot size (1.05 × 10 6–7.33 × 10 6 m −1 at 83 μm). This effect guarantees large responsivity of the proposed system for THZ-IR photodetector. In this proposal, intersublevel transitions in related states positioned at mid energies of large conduction-band-offset materials (GaN/AlGaN) are used to depress the thermal effect in dark current. Adding the resonant tunneling double barrier to the quantum dot resolves the basic problem of collecting electrons from deep excited state without applying large bias voltage. Also, employing the RT double barrier reduces the ground state dark current term. Reduction of the dark current and increasing the responsivity yields ultra-high detectivity, 5 × 10 16 and 2.25 × 10 9 cm Hz 1/2/W at 83 μm, at 83 and 300 K, respectively. Analysis of the proposed structure is done analytically.