Bipolar junction transistor based sensors for chemical and biological sensing

A bipolar junction transistor (BJT) based sensor is investigated for its sensing characteristics such as sensitivity and signal to noise ratio (SNR). The sensor consists of a bipolar transistor with its base connected to a sensing surface in contact with the solution. Measurements are performed using pH buffer solutions and the sensor sensitivity and signal to noise ratio are shown to be significantly enhanced in comparison to nanowire field effect transistor (FET) sensors. In addition to the pH sensing, detection of single strand DNA is demonstrated. Lastly, the BJT sensor also provides simultaneous temperature measurement.