| 1 | In semiconductor receivers transistors take the place of vacuum tubes. | |
| 2 | A lot of these things go back to transistors and semiconductors. | |
| 3 | Semiconductors are going to play an important part in automation and signalling. | |
| 4 | But the major ingredient of semiconductors is silicon, the second abundant element on earth. | |
| 5 | However, unlike the semiconductor silicon, graphene has no gap between its valence and conduction bands. |