Response from avalanche photodiode made with flat silicon, and with microstructured silicon. The flat silicon device shows no response below a bias of 900 V.
Output: In collaboration with Radiation Monitoring Devices, Incorporated of Watertown, MA, Mazur and Friend have developed a prototype avalance photodiode (APD) using microtextured silicon. The APD produces a signal in the infrared at 1.3 µm where ordinary silicon produces a signal only at bias voltages near the breakdown threshold.
Outcome: The subbandgap photocurrent shows great promise for a new class of infrared detectors. The demonstrated subbandgap responsivity extends the wavelength range of silicon-based detectors beyond 1.1 µm to wavelengths which are of great importance in optoelectronic communications.
Cynthia M. Friend (SEAS), and
Harvard MRSEC (DMR-0820484)