Semiconductor blue diamond

Diamonds can now be synthesized to weigh more than 0.6 g [3 carats (ct)]. This is an art for the color and clarity. The production of gem quality synthetic diamonds (Section 29.14) results in a deep yellow color. Colored diamonds tend to be more valuable than colorless ones simply because they are more rare. The Dresden Green diamond weighs 40.70 ct and is the largest known green diamond in the world. Natural red, pink, and yellow diamonds can also command prices of near 1M per ct. The danger is that diamonds can also be artificially colored by irradiating them diamond was perhaps the first irradiated gem. Blue B-doped diamond is a semiconductor while blue... 

These two subgroups are further subdivided into Types la, Ib, Ila, and lib. Type la diamonds are the most common type of naturally occurring diamond they exhibit 0.1 to 0.2 wt.% nitrogen present in small aggregates, including platelets. By contrast, nitrogen in Type Ib diamonds is dispersed substitutionaUy. Of the two Type II diamond types. Type lib is a semiconductor due to minute amounts of boron impurities and exhibits a blue color, whereas Type Ila diamonds are comparatively pure. Electric insulator ( = 7 eV.). Burns in oxygen. 

Type lib Type lib diamonds are extremely rare. Due to minute amounts of boron impurities and with nitrogen below 0.1 ppm at. N they behave as a p-type semiconductors. They exhibits a blue color (e.g., the blue Hope diamond) due to the absorption band in the tail of the infrared absorption spectrum combined with the acceptor center. 

The crystal structure of silicon is similar to that of diamond however, the Si—Si bonds (226 kJ/mol) are weaker than the C—C bonds (356 kJ/mol), and silicon is not nearly as hard. There is no graphitic allotrope of silicon. Crystalline silicon is a blue-gray, somewhat shiny, brittle element that certainly appears metallic however, it is classified as a nonmetal or metalloid because it is a semiconductor that is, at low temperatures it is an insulator. However, when heated sufficiently, its electrical conductivity increases markedly. Very pure silicon for transistors is produced by reducing silicon tetrachloride prepared by... 

Transitions between the valence and conduction bands in semiconductors. These are the origin of colour in semiconductor pigments and quantum dots. In addition to colour from bandgap transitions, introduction of dopants or impurities into semiconductors leads to localised energy levels on the dopant or impurity atoms/molecules (so-called colour centres) and transitions between these levels and those of the semiconductor conduction and valence bands become possible the colour in blue and yellow diamonds arises firom these types of transitions. 

Schottky diodes can be manufactured using boron-doped material, and some of these emit a feeble blue luminescence when forward or reverse biased (66). However, the intensity of the luminescence is much lower than that obtainable with SiC blue light-emitting diodes and many orders of magnitude weaker than the recently developed LEDs based on GaN (67). Unlike diamond or SiC, GaN is a direct-gap semiconductor, and the conversion of electrical power to light is very much more efficient. It may be possible to obtain green injection luminescence from a boron-doped diode structure, but this will not compete, in performance or price, with the commercial LEDs based on GaP. 

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