| 摘要 |
<p>A photodetector and method of detecting far infrared optical signals. In one embodiment of the present invention, the photodetector (100) has a plurality of N barriers (106), N being an integer greater than 1, each barrier (106) being a layer of a material made from a first and a second group III elements and a first group V element and characterized by a bandgap. The photodetector (100) further has a plurality of N-1 emitters (108), each emitter (108) being a layer of material made from a third group III element and a second group V element and characterized by a bandgap different from that of the barriers (106) and having at least one free carrier (122) responsive to optical signals, wherein each emitter (108) is located between two barriers (106) so as to form a heterojunction (110) at each interface between an emitter (108) and a barrier (106). Moreover, each emitter (108) is doped with a first group II, IV or VI element to cause free carriers (122) in the emitter (108), wherein at least one construction parameter of each emitter (108) causes at least one free carrier (122) to occupy a range of substantially continuously distributed energies characterized by a three dimensional Fermi level (112) and respond to optical signals (107) having wavelength in the range of 3 to 10 νm with significant absorption.</p> |
