High-performance ultraviolet photodetectors based on lattice-matched InAlN/AlGaN heterostructure field-effect transistors gated by transparent ITO films

Abstract

We demonstrate high-performance ultraviolet photodetectors (UV-PDs) based on lattice-matched (LM) InAlN/AlGaN heterostructure field-effect transistors (HFETs) gated by transparent ITO films. Low dark currents of 6.8 × 10−8 and 6.1 × 10−7 A/mm and high photocurrent gains over four and three orders of magnitude were obtained for the LM In0.12Al0.88N/Al0.21Ga0.79N and In0.10Al0.90N/Al0.34Ga0.66N HFETs, respectively. The negative threshold voltage shifts under illumination indicate that most of the photo-generated carriers are transported in the two-dimensional gas (2DEG) region around the InAlN/AlGaN interface. High peak responsivities of 2.2 × 104 and 5.4 × 104 A/W and large UV-to-visible rejection ratios greater than 104 and 103 were achieved for the LM In0.12Al0.88N/Al0.21Ga0.79N and In0.10Al0.90N/Al0.34Ga0.66N HFET-type UV-PDs, respectively. These improved performances with respect to other AlGaN UV-PDs around the same wavelength detection range may possibly be attributed to the greater contribution of the photogenerated electrons to the 2DEG, which results from the increase in the polarization sheet charge density at the InAlN/AlGaN interface. The LM InAlN/AlGaN heterostructures provide relatively promising candidates for realizing high-performance HFET-type UV-PDs.

Electronic and optical properties of core–shell InAlN nanorods: a comparative study via LDA, LDA-1/2, mBJ, HSE06, G0W0 and BSE methods

“…19,20 High-sensitivity photodetectors based on InAlN nanophotonic structure is applicable from deep DUV to NIR region. 5,7,21 With controlling composition of InAlN with In-content B0.17, strain-less multilayer InAlN/GaN-distributed Bragg reflectors (DBRs) with high a peak reflectivity can be grown directly onto nanodevices structures for fabricating vertical-cavity surface-emitting lasers (VCSELs). 22,23 To aid the development of nanodevices based on core-shell InAlN NRs, it is crucial to have a theoretical tool to test different design scenarios and to help the interpretation of the electronic properties of as-synthesized core-shell InAlN NRs.…”

“…[1][2][3]107 Therefore, many optoelectronic devices can possibly be fabricated from InAlN alloys, which are applicable in a wide wavelength range covering deep-ultraviolet (DUV) to near infrared (NIR), such as light-emitting diodes, laser diodes, solar cells, and photodetectors. [4][5][6][7][8] However, InAlN thin film often contains large number of structural defects and compositional inhomogeneity owing to a wide-range composition immiscibility of the In x Al 1Àx N (0.1 o x o 0.9), low dissociation temperature of InN (B550), and mismatches in lattice and coefficient of thermal expansion to common substrates. [9][10][11] Alternatively, InAlN grown in the form of lowdimensional nanostructures can provide an opportunity to overcome the effects of lattice mismatch like threading dislocations formation and substrate-film strain.…”

“…19,20 High-sensitivity photodetectors based on InAlN nanophotonic structure is applicable from deep DUV to NIR region. 5,7,21 With controlling composition of InAlN with In-content ∼0.17, strain-less multilayer InAlN/GaN-distributed Bragg reflectors (DBRs) with high a peak reflectivity can be grown directly onto nanodevices structures for fabricating vertical-cavity surface-emitting lasers (VCSELs). 22,23…”

Simulation Study on the Structure Design of p-GaN/AlGaN/GaN HEMT-Based Ultraviolet Phototransistors

“…In addition to the conventional photodetector configurations, phototransistors (PTs) based on AlGaN/GaN HEMT structures [8] have also been presented. Three methods of gate control have been explored, including recessed barrier gate [9][10][11], Schottky gate [12][13][14], and p-GaN gate [15][16][17]. Among these approaches, PT with a p-GaN optical gate has shown excellent comprehensive performance.…”

Enhancement of pH Tolerance in Conductive Al-Doped ZnO Nanofilms via Sequential Annealing

“…Among various electric materials, electrically conductive impurity-doped metal oxides are promising for emerging electronics because of their inherent atmospheric stability and temperature resistance. − Al-doped ZnO (AZO) films have been intensively studied as conductive metal oxide electrodes because of their high electrical conductivity and visible-light transmittance as well as abundance of resources. − However, it has been reported that deposited AZO nanofilms are easily dissolved in acidic or basic solutions, , limiting their utilization under harsh conditions. To overcome the chemical instability of AZO, the formation of a chemically stable capping layer (TiO 2 ) on AZO nanofilms has been proposed .…”