Low-temperature mobility-lifetime product in synthetic diamond

Abstract

Mobility-lifetime (µτ ) product is an important parameter that determines the performance of electronic and photonic devices. To overcome the previously reported difficulties in measuring the µτ product at cryogenic temperatures, we implement a time-resolved cyclotron resonance method to determine the carrier lifetime τ . After clarifying the difference between the AC and DC mobilities measured by the cyclotron resonance and time-of-flight methods, respectively, we demonstrate an inverse temperature dependence of the µτ product. The highest recorded µτ product of 0.2 cm 2 /V, which is approximately 100 times the room-temperature value, was obtained at 2 K for chemical-vapor-deposition diamond of the highest currently available purity.

Charge transport in single crystal CVD diamond studied at high temperatures

“…Decreasing temperature trend of the mu-tau product for both charge carrier types has been observed before in natural diamonds [39]. Continuation of the same trend was observed for high-purity scCVD diamonds in recent measurements for the low temperature region (2K-RT), demonstrating a strong increase in mu-tau with decreasing temperature [40]. However, even though there were other reports of mutau performance of high-purity synthetic diamonds at elevated temperatures [13,41], the systematic study is still missing in the available literature.…”

Carrier Mobility up to 106cm2V−1s−<

“…The hole mobility values reported here are also higher than those of electrons in diamond measured by UV-ToF [17] as shown Fig. 3e.…”

“…Very high electron mobility was reported by both TCT [15] and cyclotron resonance techniques [16][17][18]. Recent CWCR experiments enabled researchers to assess electron mobility values up to 100 × 10 6 cm 2 V −1 s −1 at 3 K [18], which is 16 times higher than previously reported TRCR values.…”

“…However, Konishi et al recently reported electron mobility values of up to 100 × 10 6 cm 2 V −1 s −1 measured by CWCR, a local probe technique, at 3 K [18]. Mobility values measured by cyclotron resonance have been explained to be higher than macroscopic measurements due to crystalline inhomogeneity [17]. For temperatures higher than T=30 K, a T −3/2 mobility dependence was observed.…”

“…Among diamond's aforementioned properties, charge carrier mobility is perhaps the most relevant property for many applications. Electron and hole mobilities in ultra-pure diamond have been thoroughly investigated over the last four decades by different Time of Flight (ToF) techniques [3,[5][6][7][8][9][10][11][12][13][14][15], also called Transient Current Techniques (TCT), and by Time Resolved and Continuous-Wave Cyclotron Resonance (TRCR [16,17] and CWCR [18]).…”