In this work, we report a favorable diamond substrate to realize semiconductor surface-enhanced Raman spectroscopy (SERS) for trace molecular probes with high sensitivity, stability, reproducibility, recyclability and universality. The boron-doped diamond (BDD) with surface hydrogenation or oxygenation has matched energy levels corresponding to the target molecules and plays a critical role in achieving SERS. The enhancement factor based on BDD substrates can reach 10⁴–10⁵, which approaches those obtained with most nanostructured compound semiconductors and is nearly 3–4 orders of magnitude higher than those of state-of-the-art single-element semiconductors (silicon, germanium, and graphene). The mechanism of SERS is determined to be charge transfer with vibronic coupling, which could enhance the molecular polarizability tensor. Because of its unique properties such as chemical inertness, wide bandgap, modulated doping, surface functionalization, biocompatibility, and high thermal conductivity, the single-element semiconductor diamond can serve a high-performance semiconductor SERS platform with applications in broad fields.

This work explores the temperature-dependent characteristic and carrier transport behavior of a heterojunction of n-WO₃ nanorods (NRs)/p-diamond. The n-type WO₃ NRs grown by the hydrothermal method were deposited on a p-type boron-doped diamond film. The p-n heterojunction devices showed good thermal stability and have rectification characteristic from room temperature up to 290 °C. With increasing temperature, the turn-on voltages were decreased, and the rectification ratios were relatively high. The calculated ideality factor of the device decreased monotonously with increased temperature. The carrier transport mechanisms at different applied bias voltages following Ohmic laws, recombination-tunneling, and space-charge-limited current conduction of the heterojunction are discussed depending on temperature.

A positive-negative (PN) junction tunneling diode ultraviolet (UV) photodetector of p-boron-doped diamond (BDD)/n-WO3 nanorods (NRs) with broad-band and good thermal stability was fabricated using heavily boron-doped degenerate semiconductor diamond (BDD) as a substrate. The operating temperature of the p-BDD/n-WO3 photodetector was increased to 300 °C through the negative differential resistance effect, benefiting from the excellent properties of diamond such as an increase in the concentration of boron atoms, a wideband gap (∼5.5 eV), and high thermal conductivity. In particular, the devices exhibited a negative differential resistance phenomenon in the range of 30–240 °C, accompanied by a rapid increase in photocurrent values and the phenomenon disappeared as the temperature rises to 300 °C. Moreover, a quick response speed (tr1 = 1.2 s), a high photocurrent (0.11 A at 5 V), a good rectification ratio (1.81), and a photo to dark current ratio (0.15) can be demonstrated in the p-BDD/n-WO3 NRs photodetector at 300 °C, indicating its excellent thermal stability. This work provides an effective way method for realizing UV photodetectors based on the negative differential resistance effect and reclaims the potential application of p-BDD/n-WO3 in high temperature semiconductor optoelectronic devices.

The ultraviolet (UV) photoresponse properties of a n-ZnO nanorods/p-diamond heterojunction were investigated by studying the dark and photo I–V characteristics. It shows typical rectifying behavior with a rectification ratio of 3.2 and 8.8 at 5 V for the dark current and the photocurrent, respectively. The turn on voltage under UV illumination is three times lower than that under the dark current and the ideality factor of the device is decreased. The forward current under UV illumination is more than 4 times higher than the dark one at 10 V whereas the leakage current shows a little increase at −10 V. The electrical transport behaviors are investigated both under the dark current and the photocurrent. The photogenerated charges and their transfer processes were analyzed by surface photovoltage (SPV) measurements.