High-detectivity nanowire photodetectors governed by bulk photocurrent dynamics with thermally stable carbide contacts.
Photodetectors fabricated from one-dimensional semiconductors are always dominated by the surface states due to their large surface-to-volume ratio. Therefore, the basic 5S requirements (high sensitivity, high signal-to-noise ratio, high spectral selectivity, high speed, and high stability) for practical photodetectors are difficult to satisfy. We report on high-temperature and high-detectivity solar-blind deep-ultraviolet (DUV) photodetectors based on β-Ga2O3 nanowires, in which the photoresponse behavior is dominated by the bulk instead of the surface states. Ohmic contact to the β-Ga2O3 nanowires was achieved by using a thermally stable tungsten carbide electrode. As a result, the DUV responsivity at 250 nm shows the highest values--4492 A W(-1) at room temperature (RT) and 3000 A W(-1) at 553 K (280 °C)--among the DUV photodetectors. The detectivity is as high as 1.26×10(16) cm Hz(1/2) W(-1) at RT, and still remains 4.1×10(14) cm Hz(1/2) W(-1) at as high a temperature as 553 K. The photocurrent dynamics from the β-Ga2O3 nanowire is discussed in terms of the bulk dominated photoresponse behavior. Other wide bandgap DUV detectors based on nanostructures could also be developed for high-temperature applications based on this work.
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, People's Republic of China.
Rujia
R
Zou
Zhenyu
Z
Zhang
Junqing
J
Hu
Liwen
L
Sang
Yauso
Y
Koide
Meiyong
M
Liao
D002244:Carbon / Q000737:chemistry*; D004566:Electrodes; D004867:Equipment Design; D008027:Light; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry; D053770:Nanowires; D010783:Photometry / Q000295:instrumentation*; D012666:Semiconductors; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors
D002244:Carbon