UV response characteristics of mixed-phase MgZnO thin films with different structure distributions, high I_uv/I_dark ratios, and fast speed MgZnO UV detectors with tunneling breakdown mechanisms

Abstract

High-performance ultraviolet (UV) detectors with both high responses and fast speeds are hard to make on homogeneous crystal semiconductor materials. Here, the UV response characteristics of mixed-phase MgZnO thin films with different internal structure distributions are studied. The mixed-phase MgZnO-based detector with the given crystal composition has a high response at both deep UV light (96 A W−1 at 240 nm) and near UV light (80 A W−1 at 335 nm). Meanwhile, because of the quasi-tunneling breakdown mechanism within the device, the high-response UV detector also shows a fast response speed (tr = 0.11 μs) and recovery speed (td1 = 26 μs) at deep UV light, which is much faster than both low-response mixed-phase MgZnO-based UV detectors with other structure constitutions and reported high-response UV devices on homogenous crystal materials. The Idark of the device is just 4.27 pA under a 5 V bias voltage, so the signal-to-noise ratio of the device reached 23852 at 5.5 uW cm−2 235 nm UV light. The new quasi-tunneling breakdown mechanism is observed in some mixed-phase MgZnO thin films that contain both c-MgZnO and h-MgZnO parts, which introduce a high response, signal-to-noise ratio, and fast speed into mixed-phase MgZnO-based UV detectors at weak deep UV light.

UV Response Characteristics of Amorphous Ga2O3 Thin Films With Different Microatom Distributions and a Low-Temperature Fabricated Ultrahigh-Performance a-Ga2O3 UV Detector

“…The decay times of the device with UV off are t d1 : 1.61 ms and t d2 : 33.07 ms. The response and decay speeds of the high-response a-Ga 2 O 3 UV detector are relatively fast among multiple types of solar-blind UV detectors based on different wide-band-gap materials. − ,− Considering the low-temperature deposition process of a-Ga 2 O 3 thin films, a-Ga 2 O 3 thin films are simple and low-cost materials in high-performance deep-UV detectors. The simple MSM structure detector on an amorphous Ga 2 O 3 thin film has an ultrahigh deep-UV response, much smaller dark noise level, ultrahigh signal-to-noise ratio, fast response, and recovery speeds simultaneously, which are difficult to achieve in crystalline material-based UV detector (β-Ga 2 O 3 , MgZnO, AlGaN, etc.)…”

“…As a potential next-generation semiconductor material, Ga 2 O 3 has a high dielectric constant, good carrier transport properties, and ultrahigh gain under solar-blind UV light. Among the multiple types of UV-sensitive materials (MgZnO, AlGaN, SnO 2 , Ga 2 O 3, and so on) used in solar-blind UV detectors, − the response of β-Ga 2 O 3 -based detector at 250 nm UV light reached 22 000 A/W, which is much higher than that of other wide-band-gap materials. Some groups have successfully decreased the I dark of the Ga 2 O 3 UV detector significantly by introducing a MOSFET device structure; the MOSFET β-Ga 2 O 3 detector has both a high response and low I dark , and the signal-to-noise ratio of the device is 8 × 10 5 .…”

High performance solar-blind UV detector with Mg0.472Zn0.528O/Mg0.447Zn0.553O double layer structure on MgO substrate

“…Therefore, MgZnO thin film is an ideal solar-blind UV sensitive material among multiple types of wide band gap materials (AlGaN, Ga 2 O 3 , SiC, and so on) [14][15][16][17][18][19][20]. Liu et al have made MSM structure mix-phase MgZnO detector with 191 A W −1 response at 250 nm deep UV light [16].…”

“…Liu et al have made MSM structure mix-phase MgZnO detector with 191 A W −1 response at 250 nm deep UV light [16]. Our group have made relative system study on the crystal structure and orientation of MgZnO thin films under different deposition condition with Mg 0.4 Zn 0.6 O and Mg 0.3 Zn 0.7 O source targets [20][21][22][23][24], and the mix-phase MgZnO detector with 96 A W −1 response at 250 nm deep UV light have been made under 500 °C low temperature with Mg 0.3 Zn 0.7 O source target [20]. Recently, multiple types of new device structure, such as MOSFET, heterojunction, 2DEG structure, have been induced to improve the performance of Solar-blind UV detectors [25][26][27][28][29].…”

Oxygen-vacancy-dependent high-performance α-Ga2O3 nanorods photoelectrochemical deep UV photodetectors

“…Currently, some wide-bandgap semiconductors, including diamond [5], AlGaN [6], MgZnO [7], AlN [8], and Ga 2 O 3 [9], etc have been investigated for applications in solar-blind photodetectors. Among those wide-bandgap semiconductors, Ga 2 O 3 is considered an excellent material for solar-blind photodetectors due to its good chemical and thermal stability [10].…”