Metody pasywacji nowoczesnych struktur detektorów podczerwieni

Shih

et al. 2016

Jpn. J. Appl. Phys.

Enhanced responsivity and detectivity values are observed for a short 30-period InAs/GaSb type-II superlattice infrared photodetector with reduced device areas. With cut-off wavelength at 4 µm, the device with the smallest device area exhibits the highest 10 K responsivity value of 15 mA/W and the corresponding detectivity value of 1.9 × 1010 cm·Hz1/2/W at 3.6 µm. The phenomenon is attributed to the increasing carrier recombination processes with increasing transport paths for photo-excited carriers with increasing device areas. The thermal images obtained by using a single-detector raster scan system have demonstrated the potential of the device for this application.

Section: Experimental Methodsmentioning

confidence: 99%

Enhanced responsivity and detectivity values of short 30-period InAs/GaSb type-II infrared photodetectors with reduced device areas

Shih

et al. 2016

Jpn. J. Appl. Phys.

Nanoscaled Films and Layers

“…As it was stated in Ref. [23], the implementation of GaSb-based alloys in device technology is depended on reproducible control of their surface properties. In this view, the real GaSb surfaces are modified by technological processes namely cutting, smoothing, or mechanical polishing of semiconductor wafer a fact that conduced to surface damage regions.…”

Section: Surface Modificationmentioning

confidence: 99%

“…The irreversibility character of the reactions implies that oxygen atoms, rather than molecules are ultimately involved in chemical bonding. It is important to note [23] that for oxygen involved there is a movement from the chemisorption concept (i.e., adsorbed layer structure is a function of underlying surface) to the complex formation concept characterized by a film with its own chemical and structural identity. The effect of Ar + ion etching on n-GaSb native oxides for different voltages and etching times can be observed from XPS spectra, i.e., C1 (0.5 kV, t 1 = 3 minutes); C2 (1 kV, t 2 = 3 minutes); C3 (1 kV, t 3 = 5 minutes); C4 (2 kV, t 4 = 10 minutes).…”

Section: Surface Modificationmentioning

confidence: 99%

Surface Modification of III-V Compounds Substrates for Processing Technology

Ghita¹,

Logofatu²,

Negrilǎ³

et al. 2017

Semiconductor materials became a part of nowadays life due to useful applications caused by characteristic properties as variable conductivity and sensitivity to light or heat. Electrical properties of a semiconductor can be modified by doping or by the application of electric fields or light; and from this view, devices made from semiconductors can be used for amplification or energy conversion. The compound semiconductor materials from III-V class experienced a qualitative leap from promising potential to nowadays technologic environment. The III-V semiconductor compounds are the material bases for electronic and optoelectronic devices such as high-electron-mobility transistors (HEMT), bipolar heterostructure transistors, IR light-emitting diodes, heterostructure lasers, Gunn diodes, Schottky devices, photodetectors, and heterostructure solar cells for terrestrial and spatial operating conditions. Among III-V semiconductor compounds, gallium arsenide (GaAs) and gallium antimonide (GaSb) are of special interest as a substrate material due to the lattice parameter match to solid solutions (ternary and quaternary) whose band gaps cover a wide spectral range from 0.8 to 4.3 μm in the case of GaSb. The solid/ solid interfaces could play a key part in the development of microelectronic device technology. In most of the cases, the initial surface of III-V compounds exposed to laboratory conditions is covered usually with native oxide layers. Various techniques for performing the surface cleaning process are used, e.g., controlled chemical etching, in situ ion sputtering, coupled with controlled annealing in vacuum and often these classic techniques are combined in order to prepare an eligible semiconductor surface to be exposed to a technological device chain. The evolution of surface native oxides in different cleaning procedures and the characteristics of as-prepared semiconductor surface were investigated by modern surface investigation techniques, i.e., X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Rutherford backscattering spectrometry (RBS) combined with electrical characterization. Surface preparation of semiconductors in particular for III-V compounds is a necessary requirement in device technology due to the existence of surface impurities and the presence of native oxides. The impurities can

“…Despite many investigations [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], a fully convincing demonstration of helical edge states in the topological insulating phase in this material system is still elusive, although the tunability between normal to topological nontrivial insulating phases was proven with a dual gated approach [14]. Due to the peculiarities of the so-called 6.1Å material system (InAs, GaSb, and AlSb), e.g., the Fermi level pinning of InAs in the conduction band [22][23][24], additional parasitic surface conducting properties of oxidized antimonides [25][26][27], and the leakage currents of the back gate via defect states [28] make it difficult to analyze transport phenomena in InAs/GaSb DQWs and to observe topological nontrivial phases via a dual gating approach.…”

mentioning

confidence: 99%

Optical tuning of the charge carrier type in the topological regime of InAs/GaSb quantum wells

et al. 2018

We study the optical tunability of the charge carrier type in InAs/GaSb double quantum wells with its type-II broken band alignment and inverted band structure. Under constant optical excitation, the majority charge carrier type switches from electron to hole. Within the majority charge carrier type transition, the coexisting minority charge carrier contribution indicates electron-hole hybridization with a nontrivial topological insulating phase. The optical tuning is attributed to the negative photoconductivity of antimonide materials in combination with a persistent charge carrier buildup of photogenerated charges at the surface and substrate side of the device, respectively. Our study of the tuning of an InAs/GaSb double quantum well heterostructure reveals that an electro-optical switching is possible and paves the way to an optical control of the phase diagram of InAs/GaSb topological insulators.