Latest News

2.       The three semiconductors used most in the construction of electroninc devices are Ge, Si and GaAs.

3.       Diode was disvovered in 1939 and transistor was descovered in 1947.

4.       In 1954 first silicon transistor was introduced.

5.       Silicon is less temprature sensitive and one of the most abundant m,aterials on Earth.

6.       First GasAs transistor was developed in early 1970s which had speed of operation five times that of silicon transistor. Today it is used consistently as base material for new high speed very large integrated circuits designs (VLSI).

7.       At room temperature there are approximately 1.5 * 10¹⁰ free electrons in 1cm³ of intrinsic silicon material that is 15000000000 (15 billion) electrons in a space smaller than a small sugar cube – an enormous number.

8.       Free carriers in GaAs have more than five times the mobility of free carriers in Si, a factor that results in response time using  GaAs electronic devices that can be upto five times those of same devices made from Si. (Relative Mobility Factor of Si is 1500, Ge is 3900 and GaAs is 8500.)

9.       Semiconductors have a negative temperature coefficient. They exhibit an increased level of conductivity with the application of heat.

10.   Ge has the smallest band gap and GaAs has the largest gap. An electron in valence band of GaAs must gain more energy than one in Si or Ge to enter into conduction band.

11.   For onductors, the overlapping of valence and conduction bands essentially results in all additional energy picked up by the electrons being dissipated in the form of heat. But for GaAs, the band gap is suficiently large to result in significant light radiation.

12.   For LEDs, the level of doping and materials chosen determine the resulting colour.