Devices and desires in the 2-4 mu m region based on antimony-containing III-V heterostructures grown by MOVPE

Abstract

The growth, by MOVPE, of a range of antimonide-based material systems suitab!e for providing devices responsive to 2-4 pm wavelength radiation is reported. Photodetectors with external quantum efficiencies of 60% at 2.2 pm have been fabricated from an InGaSb homojunction. In order to examine the possibility of tuning the wavelength of emission or detection by using a strained single quantum well (ssow) of InGaSbIGaSb this has been grown in the depletion region of a GaSb homojunction. need for conventional doping. Using the crossed-gap alignment of InAsiGaSb we can form a diode-like structure. The most promising devices have a turn-on voltage VTo of 0.7V (1 mA), and a typical reverse voltage V, = -12V (0.1 mA) and a best V, of -12 V (IO PA) for a 100 pm diameter device with some evidence of avalanche breakdown in the structure.Abrupt doping junctions have been formed between GaSb and GaAs:Si substrates. The mismatch between the layers is ameliorated by using a low-temperature buffer layer to improve the interface. Avalanche breakdown starts at -4.5 V in these structures and reverse bias currents of <IO pA at up to 2 V from unintentionally doped GaSb (uGaSb) with a carrier concentration of 1 0 ' ~ cm-3 p.Schottky barriers are an alternative to pin junctions, but they cannot be made at all on uGaSb because of the low barrier height, which is of the order of 0.2 e ! ! . We have overcome this problem using a thin capping layer of highly dislocated GaAs. Surprisingly this has been successful for both re-growth on older structures and contiguous in situ growth. These novel heterostructures have been grown to produce devices without the

Brillouin Scattering Studies of Dynamics of Polar Nanoregions in Pb[(In1/2Nb1/2)0.65Ti0.35]O3 Single Crystals

“…Cooling is an effective but rather impractical way to suppress noise because cryogenic cooling makes detectors bulky and inconvenient in use. Infrared detectors working near room temperature have been fabricated by the MOCVD technique [3,4] and moreover, theoretical results indicate that such detectors can also obtain high performance.…”

“…In this paper, theoretical analysis is explored for roomtemperature operation of infrared (IR) photovoltaic (PV) detectors based on bulk Ga x In 1−x As 1−y Sb y alloys latticematched to GaSb, which have become very important materials in recent years in the fabrication of detectors designed for 2-4 µm infrared wavelength applications [3][4][5]. The current passing the contacts of a device causes noise because of the statistical nature of the generation and recombination processes.…”

Calculation of the R0A product in n+–n–p and p+–p–n GaInAsSb infrared detectors

“…Such devices have many important applications, including gas spectroscopy analysis, remote sensing of gas pollutants, light-wave communication system using fluoride glass fibers, as well as a number of medical applications. GaInAsSb alloys have already shown their capabilities to achieve efficient lasers [2] and detectors [3][4][5]. One of the important figures of merit in the detectors is the zero-bias resistance areas product R 0 A because the value of R 0 A directly affects the detector performance expressed by the detectivity D Ã .…”