A composite quantum-dot photodetector comprising a substrate with a colloidally deposited thin film structure forming a photosensitive region, the thin film containing at least one type of a nanocrystal quantum-dot, whereby the nanocrystal quantum dots are spaced by ligands to form a lattice, and the lattice of the quantum dots has an infill material that forms an inorganic matrix that isolates the nanocrystal quantum dots from atmospheric exposure.

Embodiments of the present disclosure are directed to infrared detector devices incorporating a tunneling structure. In one embodiment, an infrared detector device includes a first contact layer, an absorber layer adjacent to the first contact layer, and a tunneling structure including a barrier layer adjacent to the absorber layer and a second contact layer adjacent to the barrier layer. The barrier layer has a tailored valence band offset such that a valence band offset of the barrier layer at the interface between the absorber layer and the barrier layer is substantially aligned with the valence band offset of the absorber layer, and the valence band offset of the barrier layer at the interface between the barrier layer and the second contact layer is above a conduction band offset of the second contact layer.

Material and antireflection structure designs and methods of manufacturing are provided that produce efficient photovoltaic power conversion from single- and multi-junction devices. Materials of different energy gap are combined in the depletion region of at least one of the semiconductor junctions. Higher energy gap layers are positioned to reduce the diode dark current and enhance the operating voltage by suppressing both carrier injections across the junction and recombination rates within the junction. Step-graded antireflection structures are placed above the active region of the device in order to increase the photocurrent.

Methods, devices, and systems for optical sensing are provided. In one aspect, an optical sensing apparatus includes: a first absorption region configured to absorb light in at least a first spectrum with visible or near infrared wavelengths; a second absorption region formed over the first absorption region, the second absorption region configured to absorb light in at least a second spectrum with near infrared or shortwave infrared wavelengths; and a third absorption region formed over the second absorption region, the third absorption region configured to absorb light in at least a third spectrum with shortwave infrared or mid-wave infrared wavelengths.

An avalanche photodiode (APD) structure, comprising an absorption layer comprising InGaAs, InGaAlAs, InGaAsP, or an InGaAs/GaAsSb type-II superlattice, an avalanche layer comprising AlGaAsSb, and a transition portion disposed between the absorption layer and the avalanche layer is disclosed. The transition portion comprises a first grading layer of InAlGaAs or InGaAsP and a first field control layer disposed between the first grading layer and the avalanche layer. The first field control layer has a bandgap between the bandgap of the absorption layer and the bandgap of the avalanche layer. In an alternative embodiment, an avalanche photodiode (APD) structure, comprising an absorption layer comprising GaAsSb, an avalanche layer comprising AlGaAsSb, and a transition portion disposed between the absorption layer and the avalanche layer. The transition portion comprises a first grading layer and one or more field control layers having a bandgap between the bandgaps of the absorption layer and the avalanche layer.

The present invention relates to techniques, including methods and devices, for optical technology. In particular, the present invention provides methods, devices, and structures for optical devices, and in particular, photo diodes, commonly called photo sensors.

The invention relates inter alia to a photoconductor (10) comprising a multilayer (13) which comprises a plurality of photoconductive semiconductor layers (131-134). According to the invention, the multilayer (13) comprises at least two sublayers (130) which each comprise at least a first photoconductive semiconductor layer (131) and a second photoconductive semiconductor layer (132), wherein the first and the second photoconductive semiconductor layer (131, 132) are doped to different degrees for each of the sublayers (130).