Germanium semiconducting properties

The crystal structure of germanium is similar to that of diamonds and sihcon, and its semiconducting properties are also similar to silicon. 

The theory outlined above was developed for group IY semiconducting elements such as silicon and germanium some of the compounds of group III and Y elements, the III-V compounds, are also covalently bonded and have similar electrical properties which can be described in terms of a band model. The best known semiconducting III-V compound is GaAs, which is exploited for both its photonic and semiconducting properties. 

Explain why you would expect germanium to have the same type of structure and semiconducting properties as silicon. 

Metalloids have some chemical and physical properties of metals and other properties of nonmetals. In the periodic table, the metalloids lie along the border between metals and nonmetals. Silicon (Si) is probably the most well-known metalloid. Some metalloids such as silicon, germanium (Ge), and arsenic (As) are semiconductors. A semiconductor is an element that does not conduct electricity as well as a metal, but does conduct slightly better than a nonmetal. The ability of a semiconductor to conduct an electrical current can be increased by adding a small amount of certain other elements. Silicon s semiconducting properties made the computer revolution possible. 

The elements that fall into this category are silicon, germanium, selenium and tellurium. Iodine shows some semiconducting properties, and phosphorus, sulfur and arsenic can each be obtained in a crystalline form that has the properties of a semiconductor, although this is not the most stable form of these elements under normal conditions. 

The tantalum carbides and silicides and tungsten carbides cited above are used for their hardness, corrosion resistance in hot environment and their semiconducting properties, while niobium alloys (niobium-germanium, niobium-aluminium...) receive much attention for their properties of superconductivity. 

Germanium is a hard, grayish white element with metallic luster but without the duc-tihty that is typical for most metals. It has the same crystal structure as diamond and is hard and brittle. Chemically, it has many similarities with silicon. Physically, it is mainly characterized by its semiconducting properties. Curiously enough the metal is transparent to infrared radiation of wavelengths 2-16 pm. 

A small group of elements, called metalloids, have properties characteristic of both metals and nonmetals. The metalloids boron, silicon, germanium, and arsenic are semiconducting elements (see Section 20.3). 

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